|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
If you wish to try something really ridiculously dangerous and unfriendly,
take LO3 (liquid ozone). It's very toxic, corrosive and could detonate, but it's more dense and has higher energy than LOX. It's also more expensive, by far.. I vague recall somebody was crazy enough to try it... I'm not sure if there is a stable (no detonation) LO2/LO3 mix... "Paul F. Dietz" wrote in message ... Peter Fairbrother wrote: I don't know of any other liquid oxidisers in use that Henry hasn't mentioned, save fluorine/ flox, which is ridiculously dangerous and unfriendly. There are some exotics, like perchloryl fluoride and nitrogen trifluoride, but I don't believe they are in use. Chlorine pentafluoride has been used in upper stages/buses, but it's extremely dangerous. Paul |
#22
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
In article ,
Michael J Wise wrote: And it has the great virtue that at room temperature, it is essentially chemically inert: only when you get it hot does it become an enthusiastic oxidizer. So if you used it to cool a Chamber that was already running with some sort of an "Ignition Mixture", could you then pump the stuff in and run it thru a catalyst? In principle, at least. The details matter a lot. Even at temperatures where it's definitely an aggressive oxidizer, it's not yet highly decomposed; quite a small initial decomposition fraction suffices when the reaction with a fuel drives the temperature up further. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
#23
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
In article QXE2b.265282$uu5.61256@sccrnsc04,
Vlad wrote: I'm not sure if there is a stable (no detonation) LO2/LO3 mix... If (dim) memory serves, yes, reasonably-safe mixtures exist, but they have two problems. The first is that they don't necessarily stay mixed -- strange things happen during boiloff, because LO2 and LO3 don't boil off at equal rates. The second is that even if you tame the handling issues, the percentage of ozone in the safe mixtures isn't high enough to make them especially attractive. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
#24
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
"Vlad" writes:
If you wish to try something really ridiculously dangerous and unfriendly, take LO3 (liquid ozone). It's very toxic, corrosive and could detonate, ....IIRC, it is also =VERY= reactive with organics, forming explosive "ozonides," so the tankage and piping must be kept even cleaner than with LOX or H2O2. but it's more dense and has higher energy than LOX. ....In fact, LH2/LO3 is even more energetic that LH2/LF2, while not producing a toxic, corrosive exhaust... It's also more expensive, by far.. I don't see why it should be more expansive "by far" --- ozone can easily be produced from oxygen via a brush discharge, and it is straightforward (albeit dangerous!) to concetrate it using a reflux condensor. (In fact, since LO3 has a significantly higher boiling point than LO2 (161.25 K vs. 90.15 K), and since ordinary LOX often contains a small concentration of LO3, if you simply leave a large dewer flask of LOX sitting out for a while, it will eventually contain a dangerous little puddle of LO3...) I'm not sure if there is a stable (no detonation) LO2/LO3 mix... Again, since ordinary LOX often contains a small concentration of LO3, yet it does not detonate, I would say that the answer must be ``yes.'' (Although whether it will not detonate at _useful_ concentrations of LO3 is another question entirely !!! :-/) As I have noted in this newsgroup before, Ozone can be "stabilized" against decomposition by freezing, and its freezing point is above the boiling point of liquid nitrogen (80.65 K vs 77 K)). Hence, it is at least _conceivable_ that a stable and even "pumpable" slurry of frozen O3 in LN2 might be still yield a significantly higher I_sp than LOX, while being less "touchy" (explosive and reactive) than LO3. (Unfortunately, I have so far been unable to find data on how the detonation sensitivity of frozen O3 compares to liquid O3... :-( -- Gordon D. Pusch perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;' |
#26
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
Earl Colby Pottinger wrote
What about dissolved solid oxidizers? I am sure I read about one atleast in the past. I remember hearing of, but not using, a 60+% w/w solution of sodium perchlorate in water for model rocketry in the 60's or 70's. Is that what you're thinking of? -- Peter Fairbrother |
#27
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
|
#28
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
It's also more expensive, by far.. I don't see why it should be more expansive "by far" --- ozone can easily be produced from oxygen via a brush discharge, and it is straightforward (albeit dangerous!) to concetrate it using a reflux condensor. (In fact, since LO3 has a significantly higher boiling point than LO2 (161.25 K vs. 90.15 K), and since ordinary LOX often contains a small concentration of LO3, if you simply leave a large dewer flask of LOX sitting out for a while, it will eventually contain a dangerous little puddle of LO3...) Because: 1. LO3 could detonate - you'll pay for safety measures and risk (LO2 is much safer) 2. LO3 is highly toxic - you'll pay for safety measures and risk (LO2 is almost not toxic) 3. O3 production is low volume - costs more, capital costs: O3 - 1000 $/(kg/h) LO2 - ~ 25 $/(kg/h) 4. O3 production requires more energy by it's nature and it's highly inefficient: O3 - ~ 9 kWh/kg LO2 - ~ 1.3 kWh/kg 5. Discharge "eats" electrodes, and frequent replacement is required (or less frequent, for gold/platinum electrodes). I bet however would agree to produce LO3 will ask at least 10 times the price of LOX, and more likely 100 - 1000 times the price. A good indication - use of O3 for water disinfection is more costly than Cl2, and Cl2 is more expensive than O2. Another good indication is a very high price of toxic N2O4. As I have noted in this newsgroup before, Ozone can be "stabilized" against decomposition by freezing, and its freezing point is above the boiling point of liquid nitrogen (80.65 K vs 77 K)). Hence, it is at least _conceivable_ that a stable and even "pumpable" slurry of frozen O3 in LN2 might be still yield a significantly higher I_sp than LOX, while being less "touchy" (explosive and reactive) than LO3. (Unfortunately, I have so far been unable to find data on how the detonation sensitivity of frozen O3 compares to liquid O3... :-( I don't see any theoretical indications why solid O3 should not detonate if liquid O3 detonates. I also don't know any similar case, when liquid detonates and solid does not. Liquids are just more sensitive, because it's more likely to create a shock wave in liquid accidentally (cavitation is one good example). I doubt solid O3 in LN2 makes any sense because of the large amount of inert N2. In a fantasy land, LHe + something to increase viscosity (to form a gel) + nanoparticles of solid O3 (nanoparticles only because they sound cool) would make a reasonable oxidizer due to very low density of LHe (and, therefore, low mass fraction of inert He) and low molecular mass of He (higher Isp at the same temperature). (if such a thing is possible is this world, it would be too expensive and too cryogenic, and in the fantasy world, why not use N5 instead of trivial O3 ?) |
#29
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
In article ,
Earl Colby Pottinger wrote: The tricky part, really, is the oxidizer. Fuels are generally cheap and straightforward. There are about four reasonable choices of oxidizer... What about dissolved solid oxidizers? I am sure I read about one atleast in the past. Nothing with performance that's worth writing home about, as far as I know. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
#30
|
|||
|
|||
Cheap, easy to handle fuels/oxidizers
Hi,
You can learn EVERYTHING you ever wanted to know about the use of LO2/LO3 slurries by reviewing the tech reports from the NASP program... If memory serves me correctly, they decided that a 12% slurry was the optimum mix for NASP. The problem with H2O2 is that there isn't anyone currently working with the stuff who has even the smallest clue what they are doing. John Carmack and his people could save them selves a world of hurt that they are setting them selves up for if only they would sit their asses down and review the literature. John, your going to get someone killed with your ignorance. N20 - Yes Henry, there is a room temperature catalyst for it. Once again, do a literature review. Just look outside the aerospace industry for the answer to that one. Lox/Methane makes a BEAUTIFULLY performing mixed monoprop. There is a 3 degree temperature overlap at which they are liquid. Operationally maintaining the mixed monoprop in that temperature range is the real trick. Here is the reason it was never used: It is photo-sensitive. At the optimum O/F ratio it has 4.61 times the explosive energy of TNT and the only thing it takes to detonate the mixture is a FLASHLIGHT. A security guard died so that we could learn this... Lox is clearly the way to go in terms of cost and performance. However, until someone invests HEAVILY in Lox Valve R&D, it will never be reliable. Frozen Lox valves are one of the most common causes of vehicle flight failures in the entire history of rocketry. I don't think there is "one" right answer though. If I was going to get back into the rocket biz, i'd use a mixed monoprop for a small launcher and Lox/hydrocarbon for a big launcher. As Always, Jay Troetschel "Henry Spencer" wrote in message ... In article , Earl Colby Pottinger wrote: The tricky part, really, is the oxidizer. Fuels are generally cheap and straightforward. There are about four reasonable choices of oxidizer... What about dissolved solid oxidizers? I am sure I read about one atleast in the past. Nothing with performance that's worth writing home about, as far as I know. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Scientists Develop Cheap Method for Solar System Hunt | Ron Baalke | Science | 0 | November 20th 03 03:55 PM |