Pre-mixing cryogenic fuels and using only one fuel tankWhy did it take so long for methane to be used as a rocket propellant?Final conclusion/description of the cause of the SpaceX Sept. 1, 2016 anomaly? What's a “buckle”?Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)How much fuel would one need to launch a 1kg object from 100,000 feet?In a cryogenic fuel rocket, at what pressure is the fuel injected into the engine?How long is it feasible to store cryogenic fuels?How are fuel tanks filled with cryogenic hydrogen?How did the Space Shuttle keep its cryogenic fuel cold?Pros and Cons of LH2/LOX vs Other FuelsManufacturing H2 and O2 rocket fuel components?Why is one of these two concurrent fuel-dump spirals blue?Safety regulations for storing, handling, and using rocket fuels?What methods are proposed for storing cryogenic fuels (esp. hydrogen) in space for months or years?
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Pre-mixing cryogenic fuels and using only one fuel tank
Why did it take so long for methane to be used as a rocket propellant?Final conclusion/description of the cause of the SpaceX Sept. 1, 2016 anomaly? What's a “buckle”?Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)How much fuel would one need to launch a 1kg object from 100,000 feet?In a cryogenic fuel rocket, at what pressure is the fuel injected into the engine?How long is it feasible to store cryogenic fuels?How are fuel tanks filled with cryogenic hydrogen?How did the Space Shuttle keep its cryogenic fuel cold?Pros and Cons of LH2/LOX vs Other FuelsManufacturing H2 and O2 rocket fuel components?Why is one of these two concurrent fuel-dump spirals blue?Safety regulations for storing, handling, and using rocket fuels?What methods are proposed for storing cryogenic fuels (esp. hydrogen) in space for months or years?
$begingroup$
A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.
Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.
Edit: Thank you to all who answered. Even the imperfect answers helped, as the comments helped me work through the whys and wherefores. I did know a methalox mixture, if it could exist, would be highly dangerous, but unsure how dangerous compared to a failure/fire of one tank causing the other tank to rupture, mixing the two. Even I can now see why the rocket scientists got it right.
fuel
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
$endgroup$
|
show 5 more comments
$begingroup$
A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.
Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.
Edit: Thank you to all who answered. Even the imperfect answers helped, as the comments helped me work through the whys and wherefores. I did know a methalox mixture, if it could exist, would be highly dangerous, but unsure how dangerous compared to a failure/fire of one tank causing the other tank to rupture, mixing the two. Even I can now see why the rocket scientists got it right.
fuel
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
$endgroup$
5
$begingroup$
But what if there is no temperature were both oxygen and methane are liquid? You may look for melting and boiling points of both methane and oxygen in wikipedia.
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– Uwe
Mar 21 at 20:48
2
$begingroup$
I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?; you may want to keep an eye on it.
$endgroup$
– uhoh
Mar 22 at 1:51
1
$begingroup$
If you use a cryogenic monopropellant mixture, how do you avoid that the ignition front in the combustion chamber is creeping back to turbo pump, pipes and finally the propellant tank? Ignition front may be much faster than creeping, it may be as fast as an explosion.
$endgroup$
– Uwe
Mar 22 at 11:58
3
$begingroup$
Why not premix them? One word: kaboom. A stray spark and you could have all the monoprpellant ignite at once.
$endgroup$
– gwally
Mar 22 at 15:01
2
$begingroup$
@BobJarvis explosive expansion is actually a well defined behaviour, just like isothermic expansion and isobaric expansion are. So explosions are indeed something "special" in the thermodynamic side of things. On the T-S curve an exposive expansion is a linear
$endgroup$
– paul23
Mar 23 at 16:30
|
show 5 more comments
$begingroup$
A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.
Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.
Edit: Thank you to all who answered. Even the imperfect answers helped, as the comments helped me work through the whys and wherefores. I did know a methalox mixture, if it could exist, would be highly dangerous, but unsure how dangerous compared to a failure/fire of one tank causing the other tank to rupture, mixing the two. Even I can now see why the rocket scientists got it right.
fuel
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
$endgroup$
A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.
Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.
Edit: Thank you to all who answered. Even the imperfect answers helped, as the comments helped me work through the whys and wherefores. I did know a methalox mixture, if it could exist, would be highly dangerous, but unsure how dangerous compared to a failure/fire of one tank causing the other tank to rupture, mixing the two. Even I can now see why the rocket scientists got it right.
fuel
fuel
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
edited Mar 21 at 23:17
SpaceInMyHead
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
asked Mar 21 at 17:20
SpaceInMyHeadSpaceInMyHead
17829
17829
5
$begingroup$
But what if there is no temperature were both oxygen and methane are liquid? You may look for melting and boiling points of both methane and oxygen in wikipedia.
$endgroup$
– Uwe
Mar 21 at 20:48
2
$begingroup$
I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?; you may want to keep an eye on it.
$endgroup$
– uhoh
Mar 22 at 1:51
1
$begingroup$
If you use a cryogenic monopropellant mixture, how do you avoid that the ignition front in the combustion chamber is creeping back to turbo pump, pipes and finally the propellant tank? Ignition front may be much faster than creeping, it may be as fast as an explosion.
$endgroup$
– Uwe
Mar 22 at 11:58
3
$begingroup$
Why not premix them? One word: kaboom. A stray spark and you could have all the monoprpellant ignite at once.
$endgroup$
– gwally
Mar 22 at 15:01
2
$begingroup$
@BobJarvis explosive expansion is actually a well defined behaviour, just like isothermic expansion and isobaric expansion are. So explosions are indeed something "special" in the thermodynamic side of things. On the T-S curve an exposive expansion is a linear
$endgroup$
– paul23
Mar 23 at 16:30
|
show 5 more comments
5
$begingroup$
But what if there is no temperature were both oxygen and methane are liquid? You may look for melting and boiling points of both methane and oxygen in wikipedia.
$endgroup$
– Uwe
Mar 21 at 20:48
2
$begingroup$
I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?; you may want to keep an eye on it.
$endgroup$
– uhoh
Mar 22 at 1:51
1
$begingroup$
If you use a cryogenic monopropellant mixture, how do you avoid that the ignition front in the combustion chamber is creeping back to turbo pump, pipes and finally the propellant tank? Ignition front may be much faster than creeping, it may be as fast as an explosion.
$endgroup$
– Uwe
Mar 22 at 11:58
3
$begingroup$
Why not premix them? One word: kaboom. A stray spark and you could have all the monoprpellant ignite at once.
$endgroup$
– gwally
Mar 22 at 15:01
2
$begingroup$
@BobJarvis explosive expansion is actually a well defined behaviour, just like isothermic expansion and isobaric expansion are. So explosions are indeed something "special" in the thermodynamic side of things. On the T-S curve an exposive expansion is a linear
$endgroup$
– paul23
Mar 23 at 16:30
5
5
$begingroup$
But what if there is no temperature were both oxygen and methane are liquid? You may look for melting and boiling points of both methane and oxygen in wikipedia.
$endgroup$
– Uwe
Mar 21 at 20:48
$begingroup$
But what if there is no temperature were both oxygen and methane are liquid? You may look for melting and boiling points of both methane and oxygen in wikipedia.
$endgroup$
– Uwe
Mar 21 at 20:48
2
2
$begingroup$
I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?; you may want to keep an eye on it.
$endgroup$
– uhoh
Mar 22 at 1:51
$begingroup$
I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?; you may want to keep an eye on it.
$endgroup$
– uhoh
Mar 22 at 1:51
1
1
$begingroup$
If you use a cryogenic monopropellant mixture, how do you avoid that the ignition front in the combustion chamber is creeping back to turbo pump, pipes and finally the propellant tank? Ignition front may be much faster than creeping, it may be as fast as an explosion.
$endgroup$
– Uwe
Mar 22 at 11:58
$begingroup$
If you use a cryogenic monopropellant mixture, how do you avoid that the ignition front in the combustion chamber is creeping back to turbo pump, pipes and finally the propellant tank? Ignition front may be much faster than creeping, it may be as fast as an explosion.
$endgroup$
– Uwe
Mar 22 at 11:58
3
3
$begingroup$
Why not premix them? One word: kaboom. A stray spark and you could have all the monoprpellant ignite at once.
$endgroup$
– gwally
Mar 22 at 15:01
$begingroup$
Why not premix them? One word: kaboom. A stray spark and you could have all the monoprpellant ignite at once.
$endgroup$
– gwally
Mar 22 at 15:01
2
2
$begingroup$
@BobJarvis explosive expansion is actually a well defined behaviour, just like isothermic expansion and isobaric expansion are. So explosions are indeed something "special" in the thermodynamic side of things. On the T-S curve an exposive expansion is a linear
$endgroup$
– paul23
Mar 23 at 16:30
$begingroup$
@BobJarvis explosive expansion is actually a well defined behaviour, just like isothermic expansion and isobaric expansion are. So explosions are indeed something "special" in the thermodynamic side of things. On the T-S curve an exposive expansion is a linear
$endgroup$
– paul23
Mar 23 at 16:30
|
show 5 more comments
7 Answers
7
active
oldest
votes
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Urged on at a similar question on Chemistry SE, it seems that the idea of mixing liquid oxygen and liquid methane is an old one. And one that, using some of the answers above, seems to be cloaked in at least some hyperbole.
Of relevance is R.L. Every and J.O. Thieme, Journal of Spacecraft and Rockets 2(5) 787-789 (1965) titled "Liquid oxygen and liquid methane mixtures as rocket monopropellants". In the introduction the authors note that previous work shows that the liquids are miscible in all proportions above 90K. Their tests show a specific impulse of almost 300 sec, and an exhaust velocity near 6000 fps.
In addition, since "shock sensitivities were reported" in the earlier work, they did some, well, vaguely disturbing experiments (hey, it was the 60's). "Tests were conducted to determine whether violent stirring or agitation, as found in an impeller-type pump, would detonate the mixture", although they didn't have any explosions there. They then went on to quantify the impact sensitivity, dropping a weight onto a stainless steel beaker of different liquid mixtures from increasing heights until an explosion occurred. Impact sensitivities of 20-60 ft-lb were discovered (these experiments were performed with open beakers of the cryogenic liquids, with light from the room shining on them - hence the hyperbole bit). They also looked at adiabatic compression as a cause of explosion and found the liquid oxygen/methane mixtures were safer than some other things like nitromethane (which really isn't that comforting).
So, it would appear that the idea of using the liquid mixture as a monopropellant isn't totally off the wall, but please do it somewhere far from me...
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
The Every & Thieme (1965) paper seems likely to be the "article seriously proposing an oxygen-methane monopropellant" mentioned by John D. Clark in the excerpt quoted by cjm. Nice find!
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– Ilmari Karonen
Mar 22 at 15:52
2
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+1 for but please do it somewhere far from me... ;-)
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– MaxW
Mar 22 at 22:03
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This is the most useful answer yet. And - safer than nitromethane, which is used at many drag race tracks. Especial thanks for winnowing out some incorrect info in some replies.
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– SpaceInMyHead
Mar 23 at 1:40
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"vaguely disturbing" - almost poetic!
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– Volker Siegel
Mar 23 at 23:43
add a comment |
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To quote John D. Clark's great book Ignition! (Chapter 11: The Hopeful Monoprops):
If Tannenbaum's mixtures were bad, that proposed at a monopropellant conference in October 1957 by an optimist from Air Products, Inc., was enough to raise the hair on the head of anybody in the propellant business. He suggested that a mixture of liquid oxygen and liquid methane would be an extra high-energy monopropellant, and had even worked out the phase diagrams of the system.* How he avoided suicide (the first rule in handling liquid oxygen is that you never, never let it come in contact with a potential fuel) is an interesting question, particularly as JPL later demonstrated that you could make the mixture detonate merely by shining a bright light on it. Nevertheless, ten years later I read an article seriously proposing an oxygen-methane monopropellant! Apparently junior engineers are allergic to the history of their own business.
answered Mar 21 at 20:34
cjmcjm
596135
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1
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If you want to obey that first rule, an engine using liquid oxygen may never be started. The combustion chamber is the place were oxygen must be mixed with fuel.
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– Uwe
Mar 21 at 20:41
8
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@Uwe, obviously he meant "until you want a raging fire" but thought it unnecessary to say.
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– cjm
Mar 21 at 20:42
9
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That's a great quote! "...by shining a light on it..." Yowza.
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– Organic Marble
Mar 21 at 20:53
8
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@OrganicMarble, that's not even close to the best quote from that book. If you haven't read it, I highly recommend it.
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– cjm
Mar 21 at 20:55
2
$begingroup$
Thanks! I was also going to post an answer quoting that exact passage (again), but you saved me the effort. Have a +1.
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– Ilmari Karonen
Mar 21 at 21:16
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show 1 more comment
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In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.
answered Mar 21 at 17:42
TristanTristan
11.1k13857
$endgroup$
22
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Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
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– Tristan
Mar 21 at 18:39
1
$begingroup$
Good news! It's on its way to the moooon!
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– David Richerby
Mar 22 at 12:06
add a comment |
$begingroup$
At STP:
- LOX's boiling point is 90.19 K
- Methane's freezing point is 90.7 K
This does not a priori prove that a solution of the two can not exist. However it does mean that they can not be handled as liquids at the same temperature, making mixing the two more difficult.
And so I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?
We know that liquid air exists which shows that LOX and LN2 can mix together. But methane is an organic molecules and we know that heavier $textC_n textH_2n+2$ hydrocarbons include oils and waxes don't like to dissolve in non-organic solvents.
The argument against premixing is the danger of ignition due to a spark or tiny localized generation of heat. As @Tristan and @PearsonArtPhoto both mention 1, 2 the SpaceX explosion "fast fire" occurred because of the presence of a combustible material in direct contact with LOX and a localized source of mechanically produced heat. See this answer and note that the situation is discussed at length in Scott Manley's video The Dumbest Mistakes In Space Exploration
Also watch the video below, discussed in more detail in Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
$endgroup$
3
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There are explosives made by mixing liquid oxygen with a fuel see. A mixture of lampblack with liquid oxygen was even stronger than dynamite.
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– Uwe
Mar 21 at 23:12
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@Uwe write an answer!! Just block-quote that source and it will be perfect!
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– uhoh
Mar 21 at 23:16
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@Uwe if you are not going to write that answer let me know, and I'll include a block quote here. Thanks!
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– uhoh
Mar 21 at 23:48
4
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Liquid oxygen and charcoal briquettes was a really popular stupid YouTube trick for a while. So Mythbusters wanted to do a "LOX tanker spills load on asphalt road, boom" item but the small tests where so violent that they couldn't get insurance coverage for the full-scale.
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– Bob Jacobsen
Mar 22 at 4:52
2
$begingroup$
@uhoh Just include the links from me into your excellent answer. Here is another one: NASA oxygen safety manual. See page 9-1 or 143: "liquid oxygen spills on pavements such as asphalt have resulted in impact-sensitive conditions that caused explosions from traffic or dropped items." The string explos is found 161 times in this document of 288 pages.
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– Uwe
Mar 22 at 11:41
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show 1 more comment
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They would stratify.
Think of oil and water.
Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.
Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
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3
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Furthermore at liquid oxygen temperatures, methane is solid. It might be possible to put them both in the liquid phase by using higher pressures, but still sounds like a very bad situation.
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– Blake Walsh
Mar 21 at 20:17
9
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-1for several problems. 1) answer is based on the wrong gas to try to make a false point about different densities. 2) answer uses false analogy because oil and water do not mix due to molecular incompatibility (oil is hydrophobic), it's got nothing to do with density, 3) answer forwards false science that density difference is the reason liquids could not mix.
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– uhoh
Mar 21 at 22:22
9
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It would stratify into CO2, H2O and debris
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– Ingolifs
Mar 22 at 2:02
4
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Liquids only stratify if they're immiscible. LOX and methane dissolve in each other; at cold enough temperatures they've got a unity molar fraction so you can dissolve as much of one in the other as you'd like.
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– Bob Jacobsen
Mar 22 at 4:47
6
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Oh, right. So the significantly different densities of ethanol and water are why vodka stratifies into two layers. Now I understa... What was that? Vodka doesn't stratify, you say?
$endgroup$
– David Richerby
Mar 22 at 12:09
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show 8 more comments
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On the chemical/physical question of whether such a mixture can exist: Yes it can.
There's a NASA report that looks into this: "ON THE SOLUBILITIES AND RATES OF SOLUTION OF GASES IN LIQUID METHANE", Hibbard and Evans, 1968 and concludes that such mixtures are possible.
Starting on page 8:
Figure 5(a) presents the curves for oxygen, argon, carbon monoxide,
and nitrogen. Also shown are the two experimental values for nitrogen.
Agreement is excellent at 99.83K and good at 110.9K. The curves for
these gases show that solubility should decrease with increasing
temperature and the nitrogen data confirm this. This figure shows the
mole fraction solubility of oxygen to be 1.0 at 90K. This means that
oxygen, which has a normal boiling temperature of 90.1K would
continuously condense in, and be miscible in all proportions, with
liquid methane at 90K. This is confirmed by reference 11 where, in a
study of the solubility of methane in liquid oxygen, it was concluded
that these formed a near-ideal solution at -297 F (90K)
(emphasis added)
Figure 5 is reproduced below. Note how the solubility of oxygen rises rapidly as temperature drops.
Reference 11 mentioned in there is "Hydrocarbon-Oxygen Systems Solubility", McKinley and Wang, 1960 (unfortunately paywalled) which also has interesting discussion of the stability (i.e. presence or absence of a tendency to explode) of various mixtures. That covers, in delightfully calm terms, why such mixtures are not commonly used: "A composition as pictured at point A (n.b. mostly one component) is safe whereas the composition at point B (i.e. rocket fuel) can be exploded".
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
$endgroup$
add a comment |
$begingroup$
For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. Even a smaller bit of fuel in oxidizer can cause enough of an explosion to start things moving, part of the reaction was with the carbon overwrap and oxygen, which had a small spark and started the larger explosion seen. In your proposed condition, only a small spark is required to cause a large explosion, as seen in the below video.
Mixing fuel and oxidizer is bad, even the slightest spark will cause it all to go up in flames. Plus there is a lot of things that can be done to optimize the flow for different conditions, flowing more oxidizer or fuel for certain conditions.
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
$endgroup$
1
$begingroup$
Yes, but it was only an anomaly. :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 18:52
4
$begingroup$
Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
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– Bob Jacobsen
Mar 21 at 19:31
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX.
$endgroup$
– uhoh
Mar 21 at 22:25
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX. The bulkhead failed later, due to the violent reaction between the carbon overwrap + LOX.
$endgroup$
– uhoh
Mar 21 at 22:52
1
$begingroup$
Bob Jacobsen, this may be the key! Propose to the Pentagon it can be weaponized, that finding a way to mix and store methalox would produce "a fuel-air explosive enhanced by a factor several thousand." Mega-funding will ensue. :-) :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 23:08
|
show 1 more comment
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7 Answers
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7 Answers
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Urged on at a similar question on Chemistry SE, it seems that the idea of mixing liquid oxygen and liquid methane is an old one. And one that, using some of the answers above, seems to be cloaked in at least some hyperbole.
Of relevance is R.L. Every and J.O. Thieme, Journal of Spacecraft and Rockets 2(5) 787-789 (1965) titled "Liquid oxygen and liquid methane mixtures as rocket monopropellants". In the introduction the authors note that previous work shows that the liquids are miscible in all proportions above 90K. Their tests show a specific impulse of almost 300 sec, and an exhaust velocity near 6000 fps.
In addition, since "shock sensitivities were reported" in the earlier work, they did some, well, vaguely disturbing experiments (hey, it was the 60's). "Tests were conducted to determine whether violent stirring or agitation, as found in an impeller-type pump, would detonate the mixture", although they didn't have any explosions there. They then went on to quantify the impact sensitivity, dropping a weight onto a stainless steel beaker of different liquid mixtures from increasing heights until an explosion occurred. Impact sensitivities of 20-60 ft-lb were discovered (these experiments were performed with open beakers of the cryogenic liquids, with light from the room shining on them - hence the hyperbole bit). They also looked at adiabatic compression as a cause of explosion and found the liquid oxygen/methane mixtures were safer than some other things like nitromethane (which really isn't that comforting).
So, it would appear that the idea of using the liquid mixture as a monopropellant isn't totally off the wall, but please do it somewhere far from me...
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
The Every & Thieme (1965) paper seems likely to be the "article seriously proposing an oxygen-methane monopropellant" mentioned by John D. Clark in the excerpt quoted by cjm. Nice find!
$endgroup$
– Ilmari Karonen
Mar 22 at 15:52
2
$begingroup$
+1 for but please do it somewhere far from me... ;-)
$endgroup$
– MaxW
Mar 22 at 22:03
$begingroup$
This is the most useful answer yet. And - safer than nitromethane, which is used at many drag race tracks. Especial thanks for winnowing out some incorrect info in some replies.
$endgroup$
– SpaceInMyHead
Mar 23 at 1:40
$begingroup$
"vaguely disturbing" - almost poetic!
$endgroup$
– Volker Siegel
Mar 23 at 23:43
add a comment |
$begingroup$
Urged on at a similar question on Chemistry SE, it seems that the idea of mixing liquid oxygen and liquid methane is an old one. And one that, using some of the answers above, seems to be cloaked in at least some hyperbole.
Of relevance is R.L. Every and J.O. Thieme, Journal of Spacecraft and Rockets 2(5) 787-789 (1965) titled "Liquid oxygen and liquid methane mixtures as rocket monopropellants". In the introduction the authors note that previous work shows that the liquids are miscible in all proportions above 90K. Their tests show a specific impulse of almost 300 sec, and an exhaust velocity near 6000 fps.
In addition, since "shock sensitivities were reported" in the earlier work, they did some, well, vaguely disturbing experiments (hey, it was the 60's). "Tests were conducted to determine whether violent stirring or agitation, as found in an impeller-type pump, would detonate the mixture", although they didn't have any explosions there. They then went on to quantify the impact sensitivity, dropping a weight onto a stainless steel beaker of different liquid mixtures from increasing heights until an explosion occurred. Impact sensitivities of 20-60 ft-lb were discovered (these experiments were performed with open beakers of the cryogenic liquids, with light from the room shining on them - hence the hyperbole bit). They also looked at adiabatic compression as a cause of explosion and found the liquid oxygen/methane mixtures were safer than some other things like nitromethane (which really isn't that comforting).
So, it would appear that the idea of using the liquid mixture as a monopropellant isn't totally off the wall, but please do it somewhere far from me...
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
The Every & Thieme (1965) paper seems likely to be the "article seriously proposing an oxygen-methane monopropellant" mentioned by John D. Clark in the excerpt quoted by cjm. Nice find!
$endgroup$
– Ilmari Karonen
Mar 22 at 15:52
2
$begingroup$
+1 for but please do it somewhere far from me... ;-)
$endgroup$
– MaxW
Mar 22 at 22:03
$begingroup$
This is the most useful answer yet. And - safer than nitromethane, which is used at many drag race tracks. Especial thanks for winnowing out some incorrect info in some replies.
$endgroup$
– SpaceInMyHead
Mar 23 at 1:40
$begingroup$
"vaguely disturbing" - almost poetic!
$endgroup$
– Volker Siegel
Mar 23 at 23:43
add a comment |
$begingroup$
Urged on at a similar question on Chemistry SE, it seems that the idea of mixing liquid oxygen and liquid methane is an old one. And one that, using some of the answers above, seems to be cloaked in at least some hyperbole.
Of relevance is R.L. Every and J.O. Thieme, Journal of Spacecraft and Rockets 2(5) 787-789 (1965) titled "Liquid oxygen and liquid methane mixtures as rocket monopropellants". In the introduction the authors note that previous work shows that the liquids are miscible in all proportions above 90K. Their tests show a specific impulse of almost 300 sec, and an exhaust velocity near 6000 fps.
In addition, since "shock sensitivities were reported" in the earlier work, they did some, well, vaguely disturbing experiments (hey, it was the 60's). "Tests were conducted to determine whether violent stirring or agitation, as found in an impeller-type pump, would detonate the mixture", although they didn't have any explosions there. They then went on to quantify the impact sensitivity, dropping a weight onto a stainless steel beaker of different liquid mixtures from increasing heights until an explosion occurred. Impact sensitivities of 20-60 ft-lb were discovered (these experiments were performed with open beakers of the cryogenic liquids, with light from the room shining on them - hence the hyperbole bit). They also looked at adiabatic compression as a cause of explosion and found the liquid oxygen/methane mixtures were safer than some other things like nitromethane (which really isn't that comforting).
So, it would appear that the idea of using the liquid mixture as a monopropellant isn't totally off the wall, but please do it somewhere far from me...
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
Urged on at a similar question on Chemistry SE, it seems that the idea of mixing liquid oxygen and liquid methane is an old one. And one that, using some of the answers above, seems to be cloaked in at least some hyperbole.
Of relevance is R.L. Every and J.O. Thieme, Journal of Spacecraft and Rockets 2(5) 787-789 (1965) titled "Liquid oxygen and liquid methane mixtures as rocket monopropellants". In the introduction the authors note that previous work shows that the liquids are miscible in all proportions above 90K. Their tests show a specific impulse of almost 300 sec, and an exhaust velocity near 6000 fps.
In addition, since "shock sensitivities were reported" in the earlier work, they did some, well, vaguely disturbing experiments (hey, it was the 60's). "Tests were conducted to determine whether violent stirring or agitation, as found in an impeller-type pump, would detonate the mixture", although they didn't have any explosions there. They then went on to quantify the impact sensitivity, dropping a weight onto a stainless steel beaker of different liquid mixtures from increasing heights until an explosion occurred. Impact sensitivities of 20-60 ft-lb were discovered (these experiments were performed with open beakers of the cryogenic liquids, with light from the room shining on them - hence the hyperbole bit). They also looked at adiabatic compression as a cause of explosion and found the liquid oxygen/methane mixtures were safer than some other things like nitromethane (which really isn't that comforting).
So, it would appear that the idea of using the liquid mixture as a monopropellant isn't totally off the wall, but please do it somewhere far from me...
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
answered Mar 22 at 14:17
Jon CusterJon Custer
27615
27615
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Jon Custer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
The Every & Thieme (1965) paper seems likely to be the "article seriously proposing an oxygen-methane monopropellant" mentioned by John D. Clark in the excerpt quoted by cjm. Nice find!
$endgroup$
– Ilmari Karonen
Mar 22 at 15:52
2
$begingroup$
+1 for but please do it somewhere far from me... ;-)
$endgroup$
– MaxW
Mar 22 at 22:03
$begingroup$
This is the most useful answer yet. And - safer than nitromethane, which is used at many drag race tracks. Especial thanks for winnowing out some incorrect info in some replies.
$endgroup$
– SpaceInMyHead
Mar 23 at 1:40
$begingroup$
"vaguely disturbing" - almost poetic!
$endgroup$
– Volker Siegel
Mar 23 at 23:43
add a comment |
$begingroup$
The Every & Thieme (1965) paper seems likely to be the "article seriously proposing an oxygen-methane monopropellant" mentioned by John D. Clark in the excerpt quoted by cjm. Nice find!
$endgroup$
– Ilmari Karonen
Mar 22 at 15:52
2
$begingroup$
+1 for but please do it somewhere far from me... ;-)
$endgroup$
– MaxW
Mar 22 at 22:03
$begingroup$
This is the most useful answer yet. And - safer than nitromethane, which is used at many drag race tracks. Especial thanks for winnowing out some incorrect info in some replies.
$endgroup$
– SpaceInMyHead
Mar 23 at 1:40
$begingroup$
"vaguely disturbing" - almost poetic!
$endgroup$
– Volker Siegel
Mar 23 at 23:43
$begingroup$
The Every & Thieme (1965) paper seems likely to be the "article seriously proposing an oxygen-methane monopropellant" mentioned by John D. Clark in the excerpt quoted by cjm. Nice find!
$endgroup$
– Ilmari Karonen
Mar 22 at 15:52
$begingroup$
The Every & Thieme (1965) paper seems likely to be the "article seriously proposing an oxygen-methane monopropellant" mentioned by John D. Clark in the excerpt quoted by cjm. Nice find!
$endgroup$
– Ilmari Karonen
Mar 22 at 15:52
2
2
$begingroup$
+1 for but please do it somewhere far from me... ;-)
$endgroup$
– MaxW
Mar 22 at 22:03
$begingroup$
+1 for but please do it somewhere far from me... ;-)
$endgroup$
– MaxW
Mar 22 at 22:03
$begingroup$
This is the most useful answer yet. And - safer than nitromethane, which is used at many drag race tracks. Especial thanks for winnowing out some incorrect info in some replies.
$endgroup$
– SpaceInMyHead
Mar 23 at 1:40
$begingroup$
This is the most useful answer yet. And - safer than nitromethane, which is used at many drag race tracks. Especial thanks for winnowing out some incorrect info in some replies.
$endgroup$
– SpaceInMyHead
Mar 23 at 1:40
$begingroup$
"vaguely disturbing" - almost poetic!
$endgroup$
– Volker Siegel
Mar 23 at 23:43
$begingroup$
"vaguely disturbing" - almost poetic!
$endgroup$
– Volker Siegel
Mar 23 at 23:43
add a comment |
$begingroup$
To quote John D. Clark's great book Ignition! (Chapter 11: The Hopeful Monoprops):
If Tannenbaum's mixtures were bad, that proposed at a monopropellant conference in October 1957 by an optimist from Air Products, Inc., was enough to raise the hair on the head of anybody in the propellant business. He suggested that a mixture of liquid oxygen and liquid methane would be an extra high-energy monopropellant, and had even worked out the phase diagrams of the system.* How he avoided suicide (the first rule in handling liquid oxygen is that you never, never let it come in contact with a potential fuel) is an interesting question, particularly as JPL later demonstrated that you could make the mixture detonate merely by shining a bright light on it. Nevertheless, ten years later I read an article seriously proposing an oxygen-methane monopropellant! Apparently junior engineers are allergic to the history of their own business.
answered Mar 21 at 20:34
cjmcjm
596135
$endgroup$
1
$begingroup$
If you want to obey that first rule, an engine using liquid oxygen may never be started. The combustion chamber is the place were oxygen must be mixed with fuel.
$endgroup$
– Uwe
Mar 21 at 20:41
8
$begingroup$
@Uwe, obviously he meant "until you want a raging fire" but thought it unnecessary to say.
$endgroup$
– cjm
Mar 21 at 20:42
9
$begingroup$
That's a great quote! "...by shining a light on it..." Yowza.
$endgroup$
– Organic Marble
Mar 21 at 20:53
8
$begingroup$
@OrganicMarble, that's not even close to the best quote from that book. If you haven't read it, I highly recommend it.
$endgroup$
– cjm
Mar 21 at 20:55
2
$begingroup$
Thanks! I was also going to post an answer quoting that exact passage (again), but you saved me the effort. Have a +1.
$endgroup$
– Ilmari Karonen
Mar 21 at 21:16
|
show 1 more comment
$begingroup$
To quote John D. Clark's great book Ignition! (Chapter 11: The Hopeful Monoprops):
If Tannenbaum's mixtures were bad, that proposed at a monopropellant conference in October 1957 by an optimist from Air Products, Inc., was enough to raise the hair on the head of anybody in the propellant business. He suggested that a mixture of liquid oxygen and liquid methane would be an extra high-energy monopropellant, and had even worked out the phase diagrams of the system.* How he avoided suicide (the first rule in handling liquid oxygen is that you never, never let it come in contact with a potential fuel) is an interesting question, particularly as JPL later demonstrated that you could make the mixture detonate merely by shining a bright light on it. Nevertheless, ten years later I read an article seriously proposing an oxygen-methane monopropellant! Apparently junior engineers are allergic to the history of their own business.
answered Mar 21 at 20:34
cjmcjm
596135
$endgroup$
1
$begingroup$
If you want to obey that first rule, an engine using liquid oxygen may never be started. The combustion chamber is the place were oxygen must be mixed with fuel.
$endgroup$
– Uwe
Mar 21 at 20:41
8
$begingroup$
@Uwe, obviously he meant "until you want a raging fire" but thought it unnecessary to say.
$endgroup$
– cjm
Mar 21 at 20:42
9
$begingroup$
That's a great quote! "...by shining a light on it..." Yowza.
$endgroup$
– Organic Marble
Mar 21 at 20:53
8
$begingroup$
@OrganicMarble, that's not even close to the best quote from that book. If you haven't read it, I highly recommend it.
$endgroup$
– cjm
Mar 21 at 20:55
2
$begingroup$
Thanks! I was also going to post an answer quoting that exact passage (again), but you saved me the effort. Have a +1.
$endgroup$
– Ilmari Karonen
Mar 21 at 21:16
|
show 1 more comment
$begingroup$
To quote John D. Clark's great book Ignition! (Chapter 11: The Hopeful Monoprops):
If Tannenbaum's mixtures were bad, that proposed at a monopropellant conference in October 1957 by an optimist from Air Products, Inc., was enough to raise the hair on the head of anybody in the propellant business. He suggested that a mixture of liquid oxygen and liquid methane would be an extra high-energy monopropellant, and had even worked out the phase diagrams of the system.* How he avoided suicide (the first rule in handling liquid oxygen is that you never, never let it come in contact with a potential fuel) is an interesting question, particularly as JPL later demonstrated that you could make the mixture detonate merely by shining a bright light on it. Nevertheless, ten years later I read an article seriously proposing an oxygen-methane monopropellant! Apparently junior engineers are allergic to the history of their own business.
answered Mar 21 at 20:34
cjmcjm
596135
$endgroup$
To quote John D. Clark's great book Ignition! (Chapter 11: The Hopeful Monoprops):
If Tannenbaum's mixtures were bad, that proposed at a monopropellant conference in October 1957 by an optimist from Air Products, Inc., was enough to raise the hair on the head of anybody in the propellant business. He suggested that a mixture of liquid oxygen and liquid methane would be an extra high-energy monopropellant, and had even worked out the phase diagrams of the system.* How he avoided suicide (the first rule in handling liquid oxygen is that you never, never let it come in contact with a potential fuel) is an interesting question, particularly as JPL later demonstrated that you could make the mixture detonate merely by shining a bright light on it. Nevertheless, ten years later I read an article seriously proposing an oxygen-methane monopropellant! Apparently junior engineers are allergic to the history of their own business.
answered Mar 21 at 20:34
cjmcjm
596135
answered Mar 21 at 20:34
cjmcjm
596135
answered Mar 21 at 20:34
cjmcjm
596135
answered Mar 21 at 20:34
cjmcjm
596135
596135
1
$begingroup$
If you want to obey that first rule, an engine using liquid oxygen may never be started. The combustion chamber is the place were oxygen must be mixed with fuel.
$endgroup$
– Uwe
Mar 21 at 20:41
8
$begingroup$
@Uwe, obviously he meant "until you want a raging fire" but thought it unnecessary to say.
$endgroup$
– cjm
Mar 21 at 20:42
9
$begingroup$
That's a great quote! "...by shining a light on it..." Yowza.
$endgroup$
– Organic Marble
Mar 21 at 20:53
8
$begingroup$
@OrganicMarble, that's not even close to the best quote from that book. If you haven't read it, I highly recommend it.
$endgroup$
– cjm
Mar 21 at 20:55
2
$begingroup$
Thanks! I was also going to post an answer quoting that exact passage (again), but you saved me the effort. Have a +1.
$endgroup$
– Ilmari Karonen
Mar 21 at 21:16
|
show 1 more comment
1
$begingroup$
If you want to obey that first rule, an engine using liquid oxygen may never be started. The combustion chamber is the place were oxygen must be mixed with fuel.
$endgroup$
– Uwe
Mar 21 at 20:41
8
$begingroup$
@Uwe, obviously he meant "until you want a raging fire" but thought it unnecessary to say.
$endgroup$
– cjm
Mar 21 at 20:42
9
$begingroup$
That's a great quote! "...by shining a light on it..." Yowza.
$endgroup$
– Organic Marble
Mar 21 at 20:53
8
$begingroup$
@OrganicMarble, that's not even close to the best quote from that book. If you haven't read it, I highly recommend it.
$endgroup$
– cjm
Mar 21 at 20:55
2
$begingroup$
Thanks! I was also going to post an answer quoting that exact passage (again), but you saved me the effort. Have a +1.
$endgroup$
– Ilmari Karonen
Mar 21 at 21:16
1
1
$begingroup$
If you want to obey that first rule, an engine using liquid oxygen may never be started. The combustion chamber is the place were oxygen must be mixed with fuel.
$endgroup$
– Uwe
Mar 21 at 20:41
$begingroup$
If you want to obey that first rule, an engine using liquid oxygen may never be started. The combustion chamber is the place were oxygen must be mixed with fuel.
$endgroup$
– Uwe
Mar 21 at 20:41
8
8
$begingroup$
@Uwe, obviously he meant "until you want a raging fire" but thought it unnecessary to say.
$endgroup$
– cjm
Mar 21 at 20:42
$begingroup$
@Uwe, obviously he meant "until you want a raging fire" but thought it unnecessary to say.
$endgroup$
– cjm
Mar 21 at 20:42
9
9
$begingroup$
That's a great quote! "...by shining a light on it..." Yowza.
$endgroup$
– Organic Marble
Mar 21 at 20:53
$begingroup$
That's a great quote! "...by shining a light on it..." Yowza.
$endgroup$
– Organic Marble
Mar 21 at 20:53
8
8
$begingroup$
@OrganicMarble, that's not even close to the best quote from that book. If you haven't read it, I highly recommend it.
$endgroup$
– cjm
Mar 21 at 20:55
$begingroup$
@OrganicMarble, that's not even close to the best quote from that book. If you haven't read it, I highly recommend it.
$endgroup$
– cjm
Mar 21 at 20:55
2
2
$begingroup$
Thanks! I was also going to post an answer quoting that exact passage (again), but you saved me the effort. Have a +1.
$endgroup$
– Ilmari Karonen
Mar 21 at 21:16
$begingroup$
Thanks! I was also going to post an answer quoting that exact passage (again), but you saved me the effort. Have a +1.
$endgroup$
– Ilmari Karonen
Mar 21 at 21:16
|
show 1 more comment
$begingroup$
In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.
answered Mar 21 at 17:42
TristanTristan
11.1k13857
$endgroup$
22
$begingroup$
Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
$endgroup$
– Tristan
Mar 21 at 18:39
1
$begingroup$
Good news! It's on its way to the moooon!
$endgroup$
– David Richerby
Mar 22 at 12:06
add a comment |
$begingroup$
In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.
answered Mar 21 at 17:42
TristanTristan
11.1k13857
$endgroup$
22
$begingroup$
Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
$endgroup$
– Tristan
Mar 21 at 18:39
1
$begingroup$
Good news! It's on its way to the moooon!
$endgroup$
– David Richerby
Mar 22 at 12:06
add a comment |
$begingroup$
In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.
answered Mar 21 at 17:42
TristanTristan
11.1k13857
$endgroup$
In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.
answered Mar 21 at 17:42
TristanTristan
11.1k13857
answered Mar 21 at 17:42
TristanTristan
11.1k13857
answered Mar 21 at 17:42
TristanTristan
11.1k13857
answered Mar 21 at 17:42
TristanTristan
11.1k13857
11.1k13857
22
$begingroup$
Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
$endgroup$
– Tristan
Mar 21 at 18:39
1
$begingroup$
Good news! It's on its way to the moooon!
$endgroup$
– David Richerby
Mar 22 at 12:06
add a comment |
22
$begingroup$
Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
$endgroup$
– Tristan
Mar 21 at 18:39
1
$begingroup$
Good news! It's on its way to the moooon!
$endgroup$
– David Richerby
Mar 22 at 12:06
22
22
$begingroup$
Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
$endgroup$
– Tristan
Mar 21 at 18:39
$begingroup$
Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
$endgroup$
– Tristan
Mar 21 at 18:39
1
1
$begingroup$
Good news! It's on its way to the moooon!
$endgroup$
– David Richerby
Mar 22 at 12:06
$begingroup$
Good news! It's on its way to the moooon!
$endgroup$
– David Richerby
Mar 22 at 12:06
add a comment |
$begingroup$
At STP:
- LOX's boiling point is 90.19 K
- Methane's freezing point is 90.7 K
This does not a priori prove that a solution of the two can not exist. However it does mean that they can not be handled as liquids at the same temperature, making mixing the two more difficult.
And so I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?
We know that liquid air exists which shows that LOX and LN2 can mix together. But methane is an organic molecules and we know that heavier $textC_n textH_2n+2$ hydrocarbons include oils and waxes don't like to dissolve in non-organic solvents.
The argument against premixing is the danger of ignition due to a spark or tiny localized generation of heat. As @Tristan and @PearsonArtPhoto both mention 1, 2 the SpaceX explosion "fast fire" occurred because of the presence of a combustible material in direct contact with LOX and a localized source of mechanically produced heat. See this answer and note that the situation is discussed at length in Scott Manley's video The Dumbest Mistakes In Space Exploration
Also watch the video below, discussed in more detail in Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
$endgroup$
3
$begingroup$
There are explosives made by mixing liquid oxygen with a fuel see. A mixture of lampblack with liquid oxygen was even stronger than dynamite.
$endgroup$
– Uwe
Mar 21 at 23:12
$begingroup$
@Uwe write an answer!! Just block-quote that source and it will be perfect!
$endgroup$
– uhoh
Mar 21 at 23:16
$begingroup$
@Uwe if you are not going to write that answer let me know, and I'll include a block quote here. Thanks!
$endgroup$
– uhoh
Mar 21 at 23:48
4
$begingroup$
Liquid oxygen and charcoal briquettes was a really popular stupid YouTube trick for a while. So Mythbusters wanted to do a "LOX tanker spills load on asphalt road, boom" item but the small tests where so violent that they couldn't get insurance coverage for the full-scale.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:52
2
$begingroup$
@uhoh Just include the links from me into your excellent answer. Here is another one: NASA oxygen safety manual. See page 9-1 or 143: "liquid oxygen spills on pavements such as asphalt have resulted in impact-sensitive conditions that caused explosions from traffic or dropped items." The string explos is found 161 times in this document of 288 pages.
$endgroup$
– Uwe
Mar 22 at 11:41
|
show 1 more comment
$begingroup$
At STP:
- LOX's boiling point is 90.19 K
- Methane's freezing point is 90.7 K
This does not a priori prove that a solution of the two can not exist. However it does mean that they can not be handled as liquids at the same temperature, making mixing the two more difficult.
And so I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?
We know that liquid air exists which shows that LOX and LN2 can mix together. But methane is an organic molecules and we know that heavier $textC_n textH_2n+2$ hydrocarbons include oils and waxes don't like to dissolve in non-organic solvents.
The argument against premixing is the danger of ignition due to a spark or tiny localized generation of heat. As @Tristan and @PearsonArtPhoto both mention 1, 2 the SpaceX explosion "fast fire" occurred because of the presence of a combustible material in direct contact with LOX and a localized source of mechanically produced heat. See this answer and note that the situation is discussed at length in Scott Manley's video The Dumbest Mistakes In Space Exploration
Also watch the video below, discussed in more detail in Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
$endgroup$
3
$begingroup$
There are explosives made by mixing liquid oxygen with a fuel see. A mixture of lampblack with liquid oxygen was even stronger than dynamite.
$endgroup$
– Uwe
Mar 21 at 23:12
$begingroup$
@Uwe write an answer!! Just block-quote that source and it will be perfect!
$endgroup$
– uhoh
Mar 21 at 23:16
$begingroup$
@Uwe if you are not going to write that answer let me know, and I'll include a block quote here. Thanks!
$endgroup$
– uhoh
Mar 21 at 23:48
4
$begingroup$
Liquid oxygen and charcoal briquettes was a really popular stupid YouTube trick for a while. So Mythbusters wanted to do a "LOX tanker spills load on asphalt road, boom" item but the small tests where so violent that they couldn't get insurance coverage for the full-scale.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:52
2
$begingroup$
@uhoh Just include the links from me into your excellent answer. Here is another one: NASA oxygen safety manual. See page 9-1 or 143: "liquid oxygen spills on pavements such as asphalt have resulted in impact-sensitive conditions that caused explosions from traffic or dropped items." The string explos is found 161 times in this document of 288 pages.
$endgroup$
– Uwe
Mar 22 at 11:41
|
show 1 more comment
$begingroup$
At STP:
- LOX's boiling point is 90.19 K
- Methane's freezing point is 90.7 K
This does not a priori prove that a solution of the two can not exist. However it does mean that they can not be handled as liquids at the same temperature, making mixing the two more difficult.
And so I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?
We know that liquid air exists which shows that LOX and LN2 can mix together. But methane is an organic molecules and we know that heavier $textC_n textH_2n+2$ hydrocarbons include oils and waxes don't like to dissolve in non-organic solvents.
The argument against premixing is the danger of ignition due to a spark or tiny localized generation of heat. As @Tristan and @PearsonArtPhoto both mention 1, 2 the SpaceX explosion "fast fire" occurred because of the presence of a combustible material in direct contact with LOX and a localized source of mechanically produced heat. See this answer and note that the situation is discussed at length in Scott Manley's video The Dumbest Mistakes In Space Exploration
Also watch the video below, discussed in more detail in Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
$endgroup$
At STP:
- LOX's boiling point is 90.19 K
- Methane's freezing point is 90.7 K
This does not a priori prove that a solution of the two can not exist. However it does mean that they can not be handled as liquids at the same temperature, making mixing the two more difficult.
And so I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?
We know that liquid air exists which shows that LOX and LN2 can mix together. But methane is an organic molecules and we know that heavier $textC_n textH_2n+2$ hydrocarbons include oils and waxes don't like to dissolve in non-organic solvents.
The argument against premixing is the danger of ignition due to a spark or tiny localized generation of heat. As @Tristan and @PearsonArtPhoto both mention 1, 2 the SpaceX explosion "fast fire" occurred because of the presence of a combustible material in direct contact with LOX and a localized source of mechanically produced heat. See this answer and note that the situation is discussed at length in Scott Manley's video The Dumbest Mistakes In Space Exploration
Also watch the video below, discussed in more detail in Why doesn't carbon fiber overwrapping in LOX catch fire? (watch this video first)
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
edited Mar 22 at 1:51
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
answered Mar 21 at 22:42
uhohuhoh
39.6k18148502
39.6k18148502
3
$begingroup$
There are explosives made by mixing liquid oxygen with a fuel see. A mixture of lampblack with liquid oxygen was even stronger than dynamite.
$endgroup$
– Uwe
Mar 21 at 23:12
$begingroup$
@Uwe write an answer!! Just block-quote that source and it will be perfect!
$endgroup$
– uhoh
Mar 21 at 23:16
$begingroup$
@Uwe if you are not going to write that answer let me know, and I'll include a block quote here. Thanks!
$endgroup$
– uhoh
Mar 21 at 23:48
4
$begingroup$
Liquid oxygen and charcoal briquettes was a really popular stupid YouTube trick for a while. So Mythbusters wanted to do a "LOX tanker spills load on asphalt road, boom" item but the small tests where so violent that they couldn't get insurance coverage for the full-scale.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:52
2
$begingroup$
@uhoh Just include the links from me into your excellent answer. Here is another one: NASA oxygen safety manual. See page 9-1 or 143: "liquid oxygen spills on pavements such as asphalt have resulted in impact-sensitive conditions that caused explosions from traffic or dropped items." The string explos is found 161 times in this document of 288 pages.
$endgroup$
– Uwe
Mar 22 at 11:41
|
show 1 more comment
3
$begingroup$
There are explosives made by mixing liquid oxygen with a fuel see. A mixture of lampblack with liquid oxygen was even stronger than dynamite.
$endgroup$
– Uwe
Mar 21 at 23:12
$begingroup$
@Uwe write an answer!! Just block-quote that source and it will be perfect!
$endgroup$
– uhoh
Mar 21 at 23:16
$begingroup$
@Uwe if you are not going to write that answer let me know, and I'll include a block quote here. Thanks!
$endgroup$
– uhoh
Mar 21 at 23:48
4
$begingroup$
Liquid oxygen and charcoal briquettes was a really popular stupid YouTube trick for a while. So Mythbusters wanted to do a "LOX tanker spills load on asphalt road, boom" item but the small tests where so violent that they couldn't get insurance coverage for the full-scale.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:52
2
$begingroup$
@uhoh Just include the links from me into your excellent answer. Here is another one: NASA oxygen safety manual. See page 9-1 or 143: "liquid oxygen spills on pavements such as asphalt have resulted in impact-sensitive conditions that caused explosions from traffic or dropped items." The string explos is found 161 times in this document of 288 pages.
$endgroup$
– Uwe
Mar 22 at 11:41
3
3
$begingroup$
There are explosives made by mixing liquid oxygen with a fuel see. A mixture of lampblack with liquid oxygen was even stronger than dynamite.
$endgroup$
– Uwe
Mar 21 at 23:12
$begingroup$
There are explosives made by mixing liquid oxygen with a fuel see. A mixture of lampblack with liquid oxygen was even stronger than dynamite.
$endgroup$
– Uwe
Mar 21 at 23:12
$begingroup$
@Uwe write an answer!! Just block-quote that source and it will be perfect!
$endgroup$
– uhoh
Mar 21 at 23:16
$begingroup$
@Uwe write an answer!! Just block-quote that source and it will be perfect!
$endgroup$
– uhoh
Mar 21 at 23:16
$begingroup$
@Uwe if you are not going to write that answer let me know, and I'll include a block quote here. Thanks!
$endgroup$
– uhoh
Mar 21 at 23:48
$begingroup$
@Uwe if you are not going to write that answer let me know, and I'll include a block quote here. Thanks!
$endgroup$
– uhoh
Mar 21 at 23:48
4
4
$begingroup$
Liquid oxygen and charcoal briquettes was a really popular stupid YouTube trick for a while. So Mythbusters wanted to do a "LOX tanker spills load on asphalt road, boom" item but the small tests where so violent that they couldn't get insurance coverage for the full-scale.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:52
$begingroup$
Liquid oxygen and charcoal briquettes was a really popular stupid YouTube trick for a while. So Mythbusters wanted to do a "LOX tanker spills load on asphalt road, boom" item but the small tests where so violent that they couldn't get insurance coverage for the full-scale.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:52
2
2
$begingroup$
@uhoh Just include the links from me into your excellent answer. Here is another one: NASA oxygen safety manual. See page 9-1 or 143: "liquid oxygen spills on pavements such as asphalt have resulted in impact-sensitive conditions that caused explosions from traffic or dropped items." The string explos is found 161 times in this document of 288 pages.
$endgroup$
– Uwe
Mar 22 at 11:41
$begingroup$
@uhoh Just include the links from me into your excellent answer. Here is another one: NASA oxygen safety manual. See page 9-1 or 143: "liquid oxygen spills on pavements such as asphalt have resulted in impact-sensitive conditions that caused explosions from traffic or dropped items." The string explos is found 161 times in this document of 288 pages.
$endgroup$
– Uwe
Mar 22 at 11:41
|
show 1 more comment
$begingroup$
They would stratify.
Think of oil and water.
Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.
Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
$endgroup$
3
$begingroup$
Furthermore at liquid oxygen temperatures, methane is solid. It might be possible to put them both in the liquid phase by using higher pressures, but still sounds like a very bad situation.
$endgroup$
– Blake Walsh
Mar 21 at 20:17
9
$begingroup$
-1for several problems. 1) answer is based on the wrong gas to try to make a false point about different densities. 2) answer uses false analogy because oil and water do not mix due to molecular incompatibility (oil is hydrophobic), it's got nothing to do with density, 3) answer forwards false science that density difference is the reason liquids could not mix.
$endgroup$
– uhoh
Mar 21 at 22:22
9
$begingroup$
It would stratify into CO2, H2O and debris
$endgroup$
– Ingolifs
Mar 22 at 2:02
4
$begingroup$
Liquids only stratify if they're immiscible. LOX and methane dissolve in each other; at cold enough temperatures they've got a unity molar fraction so you can dissolve as much of one in the other as you'd like.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:47
6
$begingroup$
Oh, right. So the significantly different densities of ethanol and water are why vodka stratifies into two layers. Now I understa... What was that? Vodka doesn't stratify, you say?
$endgroup$
– David Richerby
Mar 22 at 12:09
|
show 8 more comments
$begingroup$
They would stratify.
Think of oil and water.
Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.
Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
$endgroup$
3
$begingroup$
Furthermore at liquid oxygen temperatures, methane is solid. It might be possible to put them both in the liquid phase by using higher pressures, but still sounds like a very bad situation.
$endgroup$
– Blake Walsh
Mar 21 at 20:17
9
$begingroup$
-1for several problems. 1) answer is based on the wrong gas to try to make a false point about different densities. 2) answer uses false analogy because oil and water do not mix due to molecular incompatibility (oil is hydrophobic), it's got nothing to do with density, 3) answer forwards false science that density difference is the reason liquids could not mix.
$endgroup$
– uhoh
Mar 21 at 22:22
9
$begingroup$
It would stratify into CO2, H2O and debris
$endgroup$
– Ingolifs
Mar 22 at 2:02
4
$begingroup$
Liquids only stratify if they're immiscible. LOX and methane dissolve in each other; at cold enough temperatures they've got a unity molar fraction so you can dissolve as much of one in the other as you'd like.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:47
6
$begingroup$
Oh, right. So the significantly different densities of ethanol and water are why vodka stratifies into two layers. Now I understa... What was that? Vodka doesn't stratify, you say?
$endgroup$
– David Richerby
Mar 22 at 12:09
|
show 8 more comments
$begingroup$
They would stratify.
Think of oil and water.
Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.
Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
$endgroup$
They would stratify.
Think of oil and water.
Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.
Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
answered Mar 21 at 17:36
Dohn JoeDohn Joe
53029
53029
3
$begingroup$
Furthermore at liquid oxygen temperatures, methane is solid. It might be possible to put them both in the liquid phase by using higher pressures, but still sounds like a very bad situation.
$endgroup$
– Blake Walsh
Mar 21 at 20:17
9
$begingroup$
-1for several problems. 1) answer is based on the wrong gas to try to make a false point about different densities. 2) answer uses false analogy because oil and water do not mix due to molecular incompatibility (oil is hydrophobic), it's got nothing to do with density, 3) answer forwards false science that density difference is the reason liquids could not mix.
$endgroup$
– uhoh
Mar 21 at 22:22
9
$begingroup$
It would stratify into CO2, H2O and debris
$endgroup$
– Ingolifs
Mar 22 at 2:02
4
$begingroup$
Liquids only stratify if they're immiscible. LOX and methane dissolve in each other; at cold enough temperatures they've got a unity molar fraction so you can dissolve as much of one in the other as you'd like.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:47
6
$begingroup$
Oh, right. So the significantly different densities of ethanol and water are why vodka stratifies into two layers. Now I understa... What was that? Vodka doesn't stratify, you say?
$endgroup$
– David Richerby
Mar 22 at 12:09
|
show 8 more comments
3
$begingroup$
Furthermore at liquid oxygen temperatures, methane is solid. It might be possible to put them both in the liquid phase by using higher pressures, but still sounds like a very bad situation.
$endgroup$
– Blake Walsh
Mar 21 at 20:17
9
$begingroup$
-1for several problems. 1) answer is based on the wrong gas to try to make a false point about different densities. 2) answer uses false analogy because oil and water do not mix due to molecular incompatibility (oil is hydrophobic), it's got nothing to do with density, 3) answer forwards false science that density difference is the reason liquids could not mix.
$endgroup$
– uhoh
Mar 21 at 22:22
9
$begingroup$
It would stratify into CO2, H2O and debris
$endgroup$
– Ingolifs
Mar 22 at 2:02
4
$begingroup$
Liquids only stratify if they're immiscible. LOX and methane dissolve in each other; at cold enough temperatures they've got a unity molar fraction so you can dissolve as much of one in the other as you'd like.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:47
6
$begingroup$
Oh, right. So the significantly different densities of ethanol and water are why vodka stratifies into two layers. Now I understa... What was that? Vodka doesn't stratify, you say?
$endgroup$
– David Richerby
Mar 22 at 12:09
3
3
$begingroup$
Furthermore at liquid oxygen temperatures, methane is solid. It might be possible to put them both in the liquid phase by using higher pressures, but still sounds like a very bad situation.
$endgroup$
– Blake Walsh
Mar 21 at 20:17
$begingroup$
Furthermore at liquid oxygen temperatures, methane is solid. It might be possible to put them both in the liquid phase by using higher pressures, but still sounds like a very bad situation.
$endgroup$
– Blake Walsh
Mar 21 at 20:17
9
9
$begingroup$
-1 for several problems. 1) answer is based on the wrong gas to try to make a false point about different densities. 2) answer uses false analogy because oil and water do not mix due to molecular incompatibility (oil is hydrophobic), it's got nothing to do with density, 3) answer forwards false science that density difference is the reason liquids could not mix.$endgroup$
– uhoh
Mar 21 at 22:22
$begingroup$
-1 for several problems. 1) answer is based on the wrong gas to try to make a false point about different densities. 2) answer uses false analogy because oil and water do not mix due to molecular incompatibility (oil is hydrophobic), it's got nothing to do with density, 3) answer forwards false science that density difference is the reason liquids could not mix.$endgroup$
– uhoh
Mar 21 at 22:22
9
9
$begingroup$
It would stratify into CO2, H2O and debris
$endgroup$
– Ingolifs
Mar 22 at 2:02
$begingroup$
It would stratify into CO2, H2O and debris
$endgroup$
– Ingolifs
Mar 22 at 2:02
4
4
$begingroup$
Liquids only stratify if they're immiscible. LOX and methane dissolve in each other; at cold enough temperatures they've got a unity molar fraction so you can dissolve as much of one in the other as you'd like.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:47
$begingroup$
Liquids only stratify if they're immiscible. LOX and methane dissolve in each other; at cold enough temperatures they've got a unity molar fraction so you can dissolve as much of one in the other as you'd like.
$endgroup$
– Bob Jacobsen
Mar 22 at 4:47
6
6
$begingroup$
Oh, right. So the significantly different densities of ethanol and water are why vodka stratifies into two layers. Now I understa... What was that? Vodka doesn't stratify, you say?
$endgroup$
– David Richerby
Mar 22 at 12:09
$begingroup$
Oh, right. So the significantly different densities of ethanol and water are why vodka stratifies into two layers. Now I understa... What was that? Vodka doesn't stratify, you say?
$endgroup$
– David Richerby
Mar 22 at 12:09
|
show 8 more comments
$begingroup$
On the chemical/physical question of whether such a mixture can exist: Yes it can.
There's a NASA report that looks into this: "ON THE SOLUBILITIES AND RATES OF SOLUTION OF GASES IN LIQUID METHANE", Hibbard and Evans, 1968 and concludes that such mixtures are possible.
Starting on page 8:
Figure 5(a) presents the curves for oxygen, argon, carbon monoxide,
and nitrogen. Also shown are the two experimental values for nitrogen.
Agreement is excellent at 99.83K and good at 110.9K. The curves for
these gases show that solubility should decrease with increasing
temperature and the nitrogen data confirm this. This figure shows the
mole fraction solubility of oxygen to be 1.0 at 90K. This means that
oxygen, which has a normal boiling temperature of 90.1K would
continuously condense in, and be miscible in all proportions, with
liquid methane at 90K. This is confirmed by reference 11 where, in a
study of the solubility of methane in liquid oxygen, it was concluded
that these formed a near-ideal solution at -297 F (90K)
(emphasis added)
Figure 5 is reproduced below. Note how the solubility of oxygen rises rapidly as temperature drops.
Reference 11 mentioned in there is "Hydrocarbon-Oxygen Systems Solubility", McKinley and Wang, 1960 (unfortunately paywalled) which also has interesting discussion of the stability (i.e. presence or absence of a tendency to explode) of various mixtures. That covers, in delightfully calm terms, why such mixtures are not commonly used: "A composition as pictured at point A (n.b. mostly one component) is safe whereas the composition at point B (i.e. rocket fuel) can be exploded".
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
$endgroup$
add a comment |
$begingroup$
On the chemical/physical question of whether such a mixture can exist: Yes it can.
There's a NASA report that looks into this: "ON THE SOLUBILITIES AND RATES OF SOLUTION OF GASES IN LIQUID METHANE", Hibbard and Evans, 1968 and concludes that such mixtures are possible.
Starting on page 8:
Figure 5(a) presents the curves for oxygen, argon, carbon monoxide,
and nitrogen. Also shown are the two experimental values for nitrogen.
Agreement is excellent at 99.83K and good at 110.9K. The curves for
these gases show that solubility should decrease with increasing
temperature and the nitrogen data confirm this. This figure shows the
mole fraction solubility of oxygen to be 1.0 at 90K. This means that
oxygen, which has a normal boiling temperature of 90.1K would
continuously condense in, and be miscible in all proportions, with
liquid methane at 90K. This is confirmed by reference 11 where, in a
study of the solubility of methane in liquid oxygen, it was concluded
that these formed a near-ideal solution at -297 F (90K)
(emphasis added)
Figure 5 is reproduced below. Note how the solubility of oxygen rises rapidly as temperature drops.
Reference 11 mentioned in there is "Hydrocarbon-Oxygen Systems Solubility", McKinley and Wang, 1960 (unfortunately paywalled) which also has interesting discussion of the stability (i.e. presence or absence of a tendency to explode) of various mixtures. That covers, in delightfully calm terms, why such mixtures are not commonly used: "A composition as pictured at point A (n.b. mostly one component) is safe whereas the composition at point B (i.e. rocket fuel) can be exploded".
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
$endgroup$
add a comment |
$begingroup$
On the chemical/physical question of whether such a mixture can exist: Yes it can.
There's a NASA report that looks into this: "ON THE SOLUBILITIES AND RATES OF SOLUTION OF GASES IN LIQUID METHANE", Hibbard and Evans, 1968 and concludes that such mixtures are possible.
Starting on page 8:
Figure 5(a) presents the curves for oxygen, argon, carbon monoxide,
and nitrogen. Also shown are the two experimental values for nitrogen.
Agreement is excellent at 99.83K and good at 110.9K. The curves for
these gases show that solubility should decrease with increasing
temperature and the nitrogen data confirm this. This figure shows the
mole fraction solubility of oxygen to be 1.0 at 90K. This means that
oxygen, which has a normal boiling temperature of 90.1K would
continuously condense in, and be miscible in all proportions, with
liquid methane at 90K. This is confirmed by reference 11 where, in a
study of the solubility of methane in liquid oxygen, it was concluded
that these formed a near-ideal solution at -297 F (90K)
(emphasis added)
Figure 5 is reproduced below. Note how the solubility of oxygen rises rapidly as temperature drops.
Reference 11 mentioned in there is "Hydrocarbon-Oxygen Systems Solubility", McKinley and Wang, 1960 (unfortunately paywalled) which also has interesting discussion of the stability (i.e. presence or absence of a tendency to explode) of various mixtures. That covers, in delightfully calm terms, why such mixtures are not commonly used: "A composition as pictured at point A (n.b. mostly one component) is safe whereas the composition at point B (i.e. rocket fuel) can be exploded".
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
$endgroup$
On the chemical/physical question of whether such a mixture can exist: Yes it can.
There's a NASA report that looks into this: "ON THE SOLUBILITIES AND RATES OF SOLUTION OF GASES IN LIQUID METHANE", Hibbard and Evans, 1968 and concludes that such mixtures are possible.
Starting on page 8:
Figure 5(a) presents the curves for oxygen, argon, carbon monoxide,
and nitrogen. Also shown are the two experimental values for nitrogen.
Agreement is excellent at 99.83K and good at 110.9K. The curves for
these gases show that solubility should decrease with increasing
temperature and the nitrogen data confirm this. This figure shows the
mole fraction solubility of oxygen to be 1.0 at 90K. This means that
oxygen, which has a normal boiling temperature of 90.1K would
continuously condense in, and be miscible in all proportions, with
liquid methane at 90K. This is confirmed by reference 11 where, in a
study of the solubility of methane in liquid oxygen, it was concluded
that these formed a near-ideal solution at -297 F (90K)
(emphasis added)
Figure 5 is reproduced below. Note how the solubility of oxygen rises rapidly as temperature drops.
Reference 11 mentioned in there is "Hydrocarbon-Oxygen Systems Solubility", McKinley and Wang, 1960 (unfortunately paywalled) which also has interesting discussion of the stability (i.e. presence or absence of a tendency to explode) of various mixtures. That covers, in delightfully calm terms, why such mixtures are not commonly used: "A composition as pictured at point A (n.b. mostly one component) is safe whereas the composition at point B (i.e. rocket fuel) can be exploded".
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
answered Mar 22 at 5:08
Bob JacobsenBob Jacobsen
5,7251129
5,7251129
add a comment |
add a comment |
$begingroup$
For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. Even a smaller bit of fuel in oxidizer can cause enough of an explosion to start things moving, part of the reaction was with the carbon overwrap and oxygen, which had a small spark and started the larger explosion seen. In your proposed condition, only a small spark is required to cause a large explosion, as seen in the below video.
Mixing fuel and oxidizer is bad, even the slightest spark will cause it all to go up in flames. Plus there is a lot of things that can be done to optimize the flow for different conditions, flowing more oxidizer or fuel for certain conditions.
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
$endgroup$
1
$begingroup$
Yes, but it was only an anomaly. :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 18:52
4
$begingroup$
Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
$endgroup$
– Bob Jacobsen
Mar 21 at 19:31
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX.
$endgroup$
– uhoh
Mar 21 at 22:25
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX. The bulkhead failed later, due to the violent reaction between the carbon overwrap + LOX.
$endgroup$
– uhoh
Mar 21 at 22:52
1
$begingroup$
Bob Jacobsen, this may be the key! Propose to the Pentagon it can be weaponized, that finding a way to mix and store methalox would produce "a fuel-air explosive enhanced by a factor several thousand." Mega-funding will ensue. :-) :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 23:08
|
show 1 more comment
$begingroup$
For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. Even a smaller bit of fuel in oxidizer can cause enough of an explosion to start things moving, part of the reaction was with the carbon overwrap and oxygen, which had a small spark and started the larger explosion seen. In your proposed condition, only a small spark is required to cause a large explosion, as seen in the below video.
Mixing fuel and oxidizer is bad, even the slightest spark will cause it all to go up in flames. Plus there is a lot of things that can be done to optimize the flow for different conditions, flowing more oxidizer or fuel for certain conditions.
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
$endgroup$
1
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Yes, but it was only an anomaly. :-)
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– SpaceInMyHead
Mar 21 at 18:52
4
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Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
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– Bob Jacobsen
Mar 21 at 19:31
1
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Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX.
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– uhoh
Mar 21 at 22:25
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX. The bulkhead failed later, due to the violent reaction between the carbon overwrap + LOX.
$endgroup$
– uhoh
Mar 21 at 22:52
1
$begingroup$
Bob Jacobsen, this may be the key! Propose to the Pentagon it can be weaponized, that finding a way to mix and store methalox would produce "a fuel-air explosive enhanced by a factor several thousand." Mega-funding will ensue. :-) :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 23:08
|
show 1 more comment
$begingroup$
For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. Even a smaller bit of fuel in oxidizer can cause enough of an explosion to start things moving, part of the reaction was with the carbon overwrap and oxygen, which had a small spark and started the larger explosion seen. In your proposed condition, only a small spark is required to cause a large explosion, as seen in the below video.
Mixing fuel and oxidizer is bad, even the slightest spark will cause it all to go up in flames. Plus there is a lot of things that can be done to optimize the flow for different conditions, flowing more oxidizer or fuel for certain conditions.
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
$endgroup$
For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. Even a smaller bit of fuel in oxidizer can cause enough of an explosion to start things moving, part of the reaction was with the carbon overwrap and oxygen, which had a small spark and started the larger explosion seen. In your proposed condition, only a small spark is required to cause a large explosion, as seen in the below video.
Mixing fuel and oxidizer is bad, even the slightest spark will cause it all to go up in flames. Plus there is a lot of things that can be done to optimize the flow for different conditions, flowing more oxidizer or fuel for certain conditions.
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
edited Mar 22 at 13:26
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
answered Mar 21 at 17:51
PearsonArtPhoto♦PearsonArtPhoto
83.5k16241459
83.5k16241459
1
$begingroup$
Yes, but it was only an anomaly. :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 18:52
4
$begingroup$
Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
$endgroup$
– Bob Jacobsen
Mar 21 at 19:31
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX.
$endgroup$
– uhoh
Mar 21 at 22:25
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX. The bulkhead failed later, due to the violent reaction between the carbon overwrap + LOX.
$endgroup$
– uhoh
Mar 21 at 22:52
1
$begingroup$
Bob Jacobsen, this may be the key! Propose to the Pentagon it can be weaponized, that finding a way to mix and store methalox would produce "a fuel-air explosive enhanced by a factor several thousand." Mega-funding will ensue. :-) :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 23:08
|
show 1 more comment
1
$begingroup$
Yes, but it was only an anomaly. :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 18:52
4
$begingroup$
Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
$endgroup$
– Bob Jacobsen
Mar 21 at 19:31
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX.
$endgroup$
– uhoh
Mar 21 at 22:25
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX. The bulkhead failed later, due to the violent reaction between the carbon overwrap + LOX.
$endgroup$
– uhoh
Mar 21 at 22:52
1
$begingroup$
Bob Jacobsen, this may be the key! Propose to the Pentagon it can be weaponized, that finding a way to mix and store methalox would produce "a fuel-air explosive enhanced by a factor several thousand." Mega-funding will ensue. :-) :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 23:08
1
1
$begingroup$
Yes, but it was only an anomaly. :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 18:52
$begingroup$
Yes, but it was only an anomaly. :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 18:52
4
4
$begingroup$
Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
$endgroup$
– Bob Jacobsen
Mar 21 at 19:31
$begingroup$
Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
$endgroup$
– Bob Jacobsen
Mar 21 at 19:31
1
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX.
$endgroup$
– uhoh
Mar 21 at 22:25
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX.
$endgroup$
– uhoh
Mar 21 at 22:25
1
1
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX. The bulkhead failed later, due to the violent reaction between the carbon overwrap + LOX.
$endgroup$
– uhoh
Mar 21 at 22:52
$begingroup$
Ignition happened between the carbon overwrap of the helium tanks inside the LOX tank, not between RP-1 and LOX. The bulkhead failed later, due to the violent reaction between the carbon overwrap + LOX.
$endgroup$
– uhoh
Mar 21 at 22:52
1
1
$begingroup$
Bob Jacobsen, this may be the key! Propose to the Pentagon it can be weaponized, that finding a way to mix and store methalox would produce "a fuel-air explosive enhanced by a factor several thousand." Mega-funding will ensue. :-) :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 23:08
$begingroup$
Bob Jacobsen, this may be the key! Propose to the Pentagon it can be weaponized, that finding a way to mix and store methalox would produce "a fuel-air explosive enhanced by a factor several thousand." Mega-funding will ensue. :-) :-)
$endgroup$
– SpaceInMyHead
Mar 21 at 23:08
|
show 1 more comment
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5
$begingroup$
But what if there is no temperature were both oxygen and methane are liquid? You may look for melting and boiling points of both methane and oxygen in wikipedia.
$endgroup$
– Uwe
Mar 21 at 20:48
2
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I've just asked Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?; you may want to keep an eye on it.
$endgroup$
– uhoh
Mar 22 at 1:51
1
$begingroup$
If you use a cryogenic monopropellant mixture, how do you avoid that the ignition front in the combustion chamber is creeping back to turbo pump, pipes and finally the propellant tank? Ignition front may be much faster than creeping, it may be as fast as an explosion.
$endgroup$
– Uwe
Mar 22 at 11:58
3
$begingroup$
Why not premix them? One word: kaboom. A stray spark and you could have all the monoprpellant ignite at once.
$endgroup$
– gwally
Mar 22 at 15:01
2
$begingroup$
@BobJarvis explosive expansion is actually a well defined behaviour, just like isothermic expansion and isobaric expansion are. So explosions are indeed something "special" in the thermodynamic side of things. On the T-S curve an exposive expansion is a linear
$endgroup$
– paul23
Mar 23 at 16:30