Chemical Forums
Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: HEDM on May 05, 2014, 04:56:05 PM
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The dinitramide anion was found by the soviets since 70s however the first report on dinitramide synthesis in the west was reported by SRI-International in 1993.
Coded SRI-14 by the SRI international, they planned to synthesize hydroxylammonium dinitramide, not knowing a compound with the most insane crystal density packing was about to be made(If you check the current proposed future green oxidizer - Ammonium dinitramide's elemental analysis to this compoud, the hydrogen content and density is almost insane!)
They synthesized the compound could simply known as Hydroxylammonium-hydroxylamine-dinitramide, it's crystal packing tells another story. This compound have all of the three possible forms of hydroxylamine - protonated, neutral, and zwitterionic, and the extensive and strong intermolecular hydrogen bond ultimately gave this compound the high density.
therefore we can also call the compound Dihydorxylammonium-hydroxylamine-azaneoxide dinitramide.
This compound have the highest hydrogen density in NHO compounds I have ever seen that still have excess oxygen to spare. With so much more hydrogen content than ADN, it beats ADN's density by 0.5gm/cm3 which is incredible. Its insane cyrstal density comes from the complex network of hydroxylamine-azaneoxide-hydroxylammonium dinitramide network.
Formula =
[H3N+O-] [[NH3OH+]2]2+ [HONH2] [[N(NO2)2]2]2- Empirically N10H14O12.
contains the hydroxylamine entity in all of its three possible forms; protonated, neutral, and zwitterionic. The O----H protons for the two protonated (NH3OH)moieties are involved in very strong hydrogen bonding
interactions to both the zwitterionic (H3N+O-) and neutral (NH2OH) moieties, essentially forming associated dimers. In the former case this bond is to O¡ (H-O, 1.406A° ) while in the latter case the hydrogen bond is to N (H-N, 1.451A° ). For these hydroxylamine moieties all of the hydrogen atoms participate in one or more hydrogen bonds.
The reason why it is so amazing is simple - It produces much more gas than the currently proposed future green energetic oxidizer ADN, the oxygen balance is good, it is much denser than ADN. Its production cost is also likely to be lower than ADN due to the less weight of dinitramide anion needed to be synthesized, and finally, the specific impulse, impulse density, will give will be much much higher than ADN, if from ammonium perchlorate to ADN is a new stage of efficiency, this compound is definately a new level and posses great potential. The reported Impact sensitivity was said to be ''more impact sensitive'' than ADN. However I personally believe the purifies and finally prilled(sphrical) and preferably coated final product will be very suitable for aerospace use. Maybe making this compound into nano powder can also cover up its high impact sensitivity, which is seen in Nano HMX to normal HMX, the impact sensitivity decreased from 6.5J to 15J-20J.
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Any particular reason to copy/paste this part of the original document?
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No I actually typed this.
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Google shows this particular text also on facebook.
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If you provide a heat of formation (accurate to 10cal/g), I can tell how good (or bad, most often) this N10H14O12 is.
However, many thousands of compounds were proposed as propellants, but only 4 combinations are used because all others are unuseable or worse. For instance, the shock sensitivity of nitromethane rules it out, or the toxicity of fluor compounds, the cost of boron compounds. Methane was considered, but against its 11s improvement, users prefer the hard-to-light kerosene.
There is also a general move to liquid oxygen, instead of solids or storable liquids. I know that some oxidizers, as ionic liquid or solids, made the buzz in the recent years, but once you check their performance, it's a huge disappointment. Obviously not worth it, and one may ask whether further work is justified.
Even in tiny thrusters used for attitude control at landers or satellites, storable liquids will disappear. Satellites have electric propulsion more and more, and I've proposed techniques to store and cool cryogenic propellants, light the reaction in the chamber, pump the propellants electrically, produce cooling jackets - everything needed to switch to liquid oxygen.
Density is interesting on a launcher but far less than the specific impulse - one of the many differences with explosives, they shouldn't be taught together. Other mundane considerations that decide if a propellant is usable: is it brittle? What is its pressure exponent? What proportion of elastomer versus crystal does it take in the mixture? (Al+NH4ClO4+polybutadiene needs too much elastomer to fill the voids, sinking its performance - a hint that the oxidizer should provide much oxygen). How dangerous to manufacture, prior to use?
So don't be too disappointed if rocket designers don't adopt every new compound.
This holds for launchers mainly. Atmospheric weapons relax the need for performance and accept more varied propellants. Over a common formulation, nitrocellulose plus nitroglycerine, improvement is still possible.
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Google shows this particular text also on facebook.
Thats because I also typed that.
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If you provide a heat of formation (accurate to 10cal/g), I can tell how good (or bad, most often) this N10H14O12 is.
However, many thousands of compounds were proposed as propellants, but only 4 combinations are used because all others are unuseable or worse. For instance, the shock sensitivity of nitromethane rules it out, or the toxicity of fluor compounds, the cost of boron compounds. Methane was considered, but against its 11s improvement, users prefer the hard-to-light kerosene.
There is also a general move to liquid oxygen, instead of solids or storable liquids. I know that some oxidizers, as ionic liquid or solids, made the buzz in the recent years, but once you check their performance, it's a huge disappointment. Obviously not worth it, and one may ask whether further work is justified.
Even in tiny thrusters used for attitude control at landers or satellites, storable liquids will disappear. Satellites have electric propulsion more and more, and I've proposed techniques to store and cool cryogenic propellants, light the reaction in the chamber, pump the propellants electrically, produce cooling jackets - everything needed to switch to liquid oxygen.
Density is interesting on a launcher but far less than the specific impulse - one of the many differences with explosives, they shouldn't be taught together. Other mundane considerations that decide if a propellant is usable: is it brittle? What is its pressure exponent? What proportion of elastomer versus crystal does it take in the mixture? (Al+NH4ClO4+polybutadiene needs too much elastomer to fill the voids, sinking its performance - a hint that the oxidizer should provide much oxygen). How dangerous to manufacture, prior to use?
So don't be too disappointed if rocket designers don't adopt every new compound.
This holds for launchers mainly. Atmospheric weapons relax the need for performance and accept more varied propellants. Over a common formulation, nitrocellulose plus nitroglycerine, improvement is still possible.
You can try searching it in this paper.
http://link.springer.com/article/10.1023%2FA%3A1011362427996
If it is not there, I predict it to be around -200. Try calculating with -200.
The specific impulse might not be too high, but its density impulse should be much higher.
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Any particular reason to post this text in both places?
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I am just raising awareness of potential crystal packing hydroxylamine salts or its hydroxylamine hydrate could achieve.
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I've run Propep on this oxidizer (does it have a manageable name?), with your -200cal/g (right unit?) heat of formation, and the raw performance would be very interesting even for a launcher, provided we still want solids.
I compared with Vega's Zefiro 23 engine, with the same expansion from 95bar to 0.5bar (hence in a graphite fibre casing), and the same astounding 12% of elastomer fuel (=polybutadiene).
69% NH4ClO4 - 19% Al - 12% Htpb give isp=2814m/s and 3590K
88% competitor - 0% Al - 12% Htpb give isp=2888m/s and 3137K
66% competitor - 22% Al - 12% Htpb give isp=3043m/s and 3639K
229m/s=23s gain are worth changing the habits. More so to get rid of chlorine.
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I also checked it as an independent gas generator that rotates a turbine, in the same conditions as
http://saposjoint.net/Forum/viewtopic.php?f=66&t=2272&p=43869#p43869
100% competitor alone give isp=2497m/s and 2614K, too hot for a turbine
56% competitor - 44% water (gelled?) for +700°C give isp=1197m/s from 50bar to 5bar
that's 100m/s less than caustic amines: discussable.
66% competitor - 34% water for 1100°C (hypothetic molybdenum turbine) give 1392m/s
again 100m/s less than caustic amines.
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So if one wanted to keep solids in a launcher, your oxidizer would be convincingly more efficient - BUT please keep in mind that rocket designers want
(1) Safety
(2) Safety
(3) Safety
(4) If it burns, that's better, but not too easily please.
Presently, solid mixes for launchers can ignite just from an open flame, possibly from a spark, and then the whole plant detonates (see youTube). That's the concern #1 at solid stages.
Then, your oxidizer must have a pressure exponent <<1 to be useable. It's the decomposition speed versus pressure, which compares directly with the behaviour of a nozzle, hence tells stability.
Of course, it must be technically manageable... Presently polybutadiene is vulcanized at RT after mixing with the powders, and ammonium perchlorate has the good will not to ignite with the chemical agents. The result is not very brittle (a crack is deadly), and can adhere to the casing, and so on, and so forth.
And, yes, cost does matter.
So please keep a cool head about new propellants - very few candidates come through.
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How do you add a new compound to PROPEP code? I wanted to do that, but I wasn't sure of how.
This new compound, is just 1 compound out of many that I know, that could replace NH4ClO4(AP).
And I personally do not think this is the brightest next-generation oxidizer, but I was here just to give an example of the high density hydroxylamine's salt and its own hydroxylamine hydrate could do.
BTW, for the unit for HOF of the compound, I meant to say -200 kj/mol. Although It might be closer to around -100kj/mol.
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Propep takes easily new compounds, and can be used in abnormal ways, that's why I didn't switch to convenient software like LRA (a free version exists), which is less touchy, more recent and quicker
http://propulsion-analysis.com/
Just edit propellant.dat as any text, preferibly with an editor that can use a fixed width font, like Courier New in Metapad
http://liquidninja.com/metapad/download.html
For instance your unpronounceable compound:
2120 HEDM's thingy 14H 12O 10N 0 0 0 -200 .0000]
- Where you want, one line per compound (must be a Fortran program)
- The line number doesn't matter
- ALIGNMENT does matter! Imitate existing compounds.
Beware this forum may remove spaces in my message.
- Compound name is rather free.
- Atoms in any order
- cal/g (here mistaken -200cal/g instead of -200kJ/mol)
- Optional density in pound per cubic inch
Unit converter for Win : SIKonverter (Ger and Eng) http://si-konverter.giga.de/
or there http://joshmadison.com/software/convert
I join my propellant.dat, so you see how heavily edited it is. Remove the txt extension before unzipping. My additions are at the top.
An accurate heat of formation is necessary to evaluate a propellant. 10cal/mol uncertainty biasses already the comparisons.
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[snip] I personally do not think this is the brightest next-generation oxidizer, but I was here just to give an example of the high density hydroxylamine's salt and its own hydroxylamine hydrate could do. [snip]
I have no firm opinion about what shall replace ammonium perchlorate in solid grain. Dinitramides' performance is better, but safety comes first, process adequacy second.
The near bright future I see for energetic compounds is, dissolved in water or maybe some alcohol or amine, as an auxiliary gas generator that rotates the turbopump(s) for the main propellants:
http://www.scienceforums.net/topic/82965-gas-generator-cycle-for-rocket-engines-variants/#entry805364
Most often a secondary, detuned mix of the the main propellants burns in an auxiliary chamber to rotate the turbopump(s), is this is harder to start (Soyuz is an exception). I'd have a graphite-fibre pressure vessel holding a separate, unpumped propellant to power the turbo-pump. Then, a monopropellant is better and can differ from the main propellants.
This auxiliary monopropellant (liquid or solid) must provide lukewarn gas (600-700°C for nickel alloys, maybe 1100°C with molybdenum as I suggest) at high speed. Dinitramides, being very soluble in water and (flammable!) methanol, have a decisive advantage over nitrates. I had to mix a fuel (diamino-guanidinium-nitrate) with ammonium dinitramide and water to get performance; if feasible, diamino-guanidinium-dinitramide would improve, or a similar compound a bit fuel-rich.
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Alright, Ill try to figure out how to make a new compound in PROPEP, i am a program-blind person. I mean, I don't know anything in this field - computer related things.
I read your idea on a good propellant, I do agree your idea is better than many existing liquid engines and that mono-liquid-propellant could reduce the overall complexity of the machine, etc.
Some of my recent ideas on favorable propellant formulation
Note - (I'm just going to type this in rush, and if i make a lot of grammar mistakes, try understand it, ill edit tomorrow when I have a nice rest)
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Interesting. I still believe solid is the answer to heavy duty launchers.
We can't use nuclear or solar sails on earth, only in space, due to the risk, pollution, etc etc. Plasma, electric, gas accelerators like VASIMIR, etc, produce low thrust only feasible in deep space.
Therefore Solid will have a very bright future if the Specific impulse could be reached.
"A 1% increase in specific impulse increases the ICBM range by 365 nautical miles (for a 5000 nautical miles ICBM) or more than 7%. A 5% specific impulse increase results in a nearly 45% range increase..."
-S. S. Penner, The Chemistry of Propellants: A Meeting Organised by the AGARD Combustion and Propulsion Panel.
Solid > Liquid in terms of complexity, and therefore cost of casing, machining, and overall safety. Liquid engine also have a much lower Fuel-payload ratio or Fuel-Casing ratio. If we can just add for example 10 seconds of impulse to SRB's, the paylaod would increase a lot.
I am not only talking about dinitramides. Solid fuels are also in great advance.
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A line to separate my idea, I read your idea about dissolving the compound in water and dissolve another fuel for a mono-liquid-propellant. Not too bad, but honestly the Isp is could not exceed 300 due to the water in the solution. I have personally tested the first propellant that dissolves an oxidizer, where the solvent is cured, into a polymer, and the amount of oxidizer is dissolved in the ''cured'' solution could provide enough oxygen for the entire system to combust.
I published this last year, I'd work on better oxidizers next time on this idea. I was just showing that such idea is possible -
http://article.sapub.org/pdf/10.5923.j.aerospace.20140301.01.pdf
Any way, I think the future to solid propellants could be low molecular weight exhaust producing salts or compounds.
Carbon, chlorine, etc, from HTPB and AP produce high molecular weight exhausts and therefore results in low Isp. So to combine these 2 advantages of solid and liquid, we might need to find a high Hydrogen or nitrogen weight fuel along with high oxygen and hydrogen density oxidizer. So our goal is find solid compounds with maximum Hydrogen, oxygen, nitrogen content by weight, in this order. We should avoid or make least out of carbon. For example, Hydrazine is a very good liquid fuel because it's cost is low, burns to form only nitrogen and water, which have low molecular weight. Amazing. However its salts and its hydrates of its own salts, which is solid, might be better, for example -
Hydrazinium azide hydrazinate = (+N2H5)(N3-)•(N2H4) or empirically N7H9, contains 91.5% nitrogen by weight. With a density at around 1.3g/cm3, would serve as an amazing solid fuel in replacement of aluminum.
http://onlinelibrary.wiley.com/doi/10.1002/1521-4087(200110)26:4%3C161::AID-PREP161%3E3.0.CO;2-O/abstract
This compound is also insensitive to shock and is very safe. It's also not hygroscopic, which is desirable. However many other properties such as compatibility with binders are not yet reported, although I predict to be compatible with most binders.
And for replace of aluminum, aluminum hydride is also promising, direct replacement of aluminum to aluminum hydride result in much higher burn-out velocity.
See this post I made -
http://www.sciencemadness.org/talk/viewthread.php?tid=29786
Now another solid salt which is interesting - Hydroxylammonium-hydroxylamine-nitrate. (NH3OH)+ (NO3)- •(NH2OH).
Reported here - http://pubs.acs.org/doi/abs/10.1021/i360030a021
Might be interesting. The density is high for the amount of gas it can produce which is - 1.7g/cm3. The salt is reported the be non-hygroscopic, and maybe, I wish, to be insensitive and safe.
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Now if we combine these 2 compounds, (NH3OH)+ (NO3)- •(NH2OH) with (+N2H5)(N3-)•(N2H4), or empirically (N3H7O5) and (N7H9), we can make an oxygen balanced mixture at molar ratio of 3:1.
The product it produces would be (N3H7O5)3(N7H9)1 > Combust > 8N2 + 15H2O. Which is 54.7% Water.
If we took N2H4 with liquid oxygen, it would be N2H4 + O2 > Combust > N2 + 2H2O. which is 56.3% Water.
The molecular product of the exhaust is almost the same, however the solid one have a density of around 1.6, while the liquid would be 1.1
See the advantage of the solid here?
That'd be my final objective in researching on this field :p
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So yeah, the most favorable propellant additive need to need to have these properties-
large amount of low-molecular-weight exhaust,
have good heat of formation for higher combustion temperature.
Low shock, electric, flame sensitivity
Able to be produced on industrial scale
compatibile with modern and energetic binders/plasticizers
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The solid-versus-liquid debate is little technical and very much a matter of which company, state or country supplies the market. In the USA, it was even a decision by congressmen that the SLS would use solids. In Europe, the choice is biassed right from the beginning. In addition, strong liquid engines existed essentially in the Soviet Union.
Fact is that every single recent cheap launcher (Falcon, Zenit, and some Chinese coming up) has liquids everywhere.
Vega was to be cheap thanks to solids and efficient with its graphite fibre casings, but now this small launcher is as expensive as a medium-class liquid like Falcon.
In the launch cost, one must factor the production and operation risks. A plant storing 500t or 3000t of explosive stuff sensitive to flame or sparks is a huge and costly risk.
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Hydrazine is an extremely bad propellant because it's risky. Performance won't rehabilitate it. Huge efforts are under way to replace it. Can you produce your hydrazinium compounds without using hydrazine at the plant? If not, it's a bad idea, even if the final product is a nonvolatile solid.
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The real criterion about a propellant, once it's safe and useable, is the specific impulse. While hydrogen is desired, there is no fixed preference between nitrogen and carbon - it all depends on the combustion enthalpy per mass unit, and the ease of gas expansion (gamma). CO (solids use to produce little CO2) is as light as N2. And Al2O3 has the worst possible mass per gas mole for being a solid, but it's very useful because it brings heat, so the comparison isn't very easy.
The stress put on density and on nitrogen proportion relates with explosives and missiles. Launcher propellants have different needs. "Energetic compounds" shouldn't be taught together.
Yes, aluminium hydride is interesting, but with a limited gain. Aluminium lithium hydride as well. They must be protected; one researcher proposed thin aluminium shells around each hydride speck. Available in Propep, so just make a few comparison runs.
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My objective with aqueous solutions of energetic salts is not to challenge the specific impulse of the main engines. Other people try it, and are very far from that goal - I expect it will stay so, because H-O bonds have nothing to do in an unburnt propellant.
Rather, I propose to produce that way the secondary flux for the turbine. Here the needs are a regular and predictable low temperature, no solids (no soot) in the gas, and only once this is met, a high expansion speed - in this particular use, water has its place and dissolved dinitramides seem to be a good choice.
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What do I do with that program by the way? Can you tell me step by step how do I add propep formulation?
Hydrazine is alright, the toxicity dosnt matter, its about the end products after combustion, hydrazine is one of the cleanest fuel. Hydrazine is used by the chinese launchers for over 100 times in the last decade due to its high density. Liquid hydrogen have a density of 0.07g/cm3, I believe we can find a better fuel than that.
As I already said.
"A 1% increase in specific impulse increases the ICBM range by 365 nautical miles (for a 5000 nautical miles ICBM) or more than 7%. A 5% specific impulse increase results in a nearly 45% range increase..."
-S. S. Penner, The Chemistry of Propellants: A Meeting Organised by the AGARD Combustion and Propulsion Panel.
Hydrazinium azide hydrazinate have a hydrogen density of 0.11, which is good enough for replacing liqui hydrazin. Aluminum hydride is also promising for a change. The cost is high for these materials, however I believe it is needed one day when you need to launch a whole space station. You're not going to expand the diameter of the rocket a lot, there is a mechanical limit of these materials, so the you need to make the fuel more efficient.
The price is worth it. When we start using the space much more regularly, we can afford it. Just like how people are willing to pay double price for premium seats on air travel, every second added to the propellant's efficiency can significantly increase the payload which is beneficial for launching a bigger piece of space station or space base. Liquid engines have a limit on its size, even the biggest liquid engine ever built produce thrust less than half of the side booster used by nasa's space shuttle launches.
Your idea probably fit best on linear aerospike engines. They can out-perform a normal engine by around 20-30%. Since liquid-mono-propellant is much less complex, it can utilize the advantage on linear aerospikes since normal liquid engine have complex oxidizer fuel pumps around these smaller thrusters.
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I know hydrazine has been and is used, as well by Proton in big amounts. But everyone wants to go away from it, because the fuel's toxicity matters an awful lot, not just the exhaust. And again, density isn't so important at a launcher, that's why hydrogen is the very best of all fuels for performance. So much that Delta uses it at the first stage.
If not hydrogen, the natural choice is RP-1 or RG-1, usually called kerosene. Practically as efficient as hydrazine, but nontoxic and nonflammable, which changes everything at the launch operations and the induced cost.
Instead of Penner's claims, you could make your own opinion. By the way, 5% more specific impulse would be 15s over RP-1 for instance, and this would be a greater improvement than any dreamed fuel achieves - an excellent reason why designers stick at the safe RP-1. But the advantage of oxygen+rekosene over solids is 40s, that's why solids are disregarded.
To compare: the recent and much improved Vega has 3 solid stages plus a small liquid stage just to reach the Low-Earth-Orbit, while Falcon and Zenit reach the higher Geosynchronous Transfer Orbit with two liquid stages. This does make a cost difference. And two light hydrogen stages would reach the geosynchronous orbit directly.
Rocket designers don't pay so much attention to hydrogen fraction or nitrogen-to-carbon. What matters is (1) Safety (2) Practical operation (3) Specific impulse. Once (1) and (2) are fulfilled, the way your achieve (3) is your matter and doesn't result directly from such ratios. But for sure, solids won't compete with liquid oxygen.
Liquids don't need to push as strongly as solids, because a liquid launcher is so much lighter. Vega puts ridiculous 1.7% of its start mass on LEO, Falcon 2.6%, Delta IV M 3.8% thanks to hydrogen.
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Again, I have no desire to use a monopropellant as the main propellant. They are far too bad.
Only at the auxiliary flux that drives the turbopump.
The aerospike doesn't gain that much, and simpler methods are nearly as good.
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How to add compounds in Propellant.dat: look at the examples. Remember the units: cal/g and LB/in3.
Propep is historically an Ms-Dos programme (and even older than Dos supposedly), on which graphical interfaces were added. Mine is Cpropepshell found there (seems 404)
www.dark.dk/download
seems to be here now
http://users.cybercity.dk/~dko7904/cpropepshell/cpropepshell.htm
but others are good as well, like Guipep
http://www.lekstutis.com/Artie/PEP/
http://www.lekstutis.com/Artie/PEP/GuiPep.zip
http://www.ibiblio.org/pub/archives/rec.models.rockets/PROGRAMS
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I talked about hydrogen density and hydrogen content because hydrogen is the most desired exhaust a rocket propellant wants because it gives the highest performance. So the hydrogen count directly effect the specific impulse of a propellant. Again, you obvious can't just look at hydrogen, in my opinion NHO salts is perfect for solid propellants due to NHO compound's these characteristics. They can give very high hydrogen content, exhaust is totally gaseous, hydrogen bonding is extensive(Can you find a compound composed of only NHO atoms that does not have hydrogen bonding? none! or many few exceptions but none to my knowledge.), and it's energy content can vary(With HTPB, GAP, Aluminum powder, mixtures of these with NHO salts such as AN/ADN/HDN/HHDN/ can vary a lot, for example - Ammonium nitrate can give specific impulses around 150-220, ammoninium dinitramide can give specific impulses of around 240-320, hydrazininium dinitramide can push addition of another 5-10 seconds, and hydroxylammonium-hydroxylamine-dinitramide can give around 15 seconds more). To my knowledge, one of the best formulation to existent solid propellant can achieve an Isp of around 340-370, which is higher than Kerosene/LOX mixture, while having much higher density.
The density matters! The higher the density, the more fuel could be out into the same area, more potential thrust is carried. This means a rocket is able to fly higher with more fuel obviously, the reason why hydrogen is not used in many rockets is due to its very low density (0.07).
If polynitrogen materials are synthesized, which is possible (N5+ cation is synthesized, or 5,5'-bistetrazole or azo1,1'bistetrazole is chemically possible) These would have specific impulse of around 500-700, however their price will probably never make it to industrial production.
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btw, which propep did you download? my propep is just 1 single application, theres no other file i can extract or do anything to, such as editing.
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Your figures about the specific impulse are far off. 370s or 340s won't be achieved by solid propellants. Your sources are quite wrong, you can throw them away.
Density is widely uninteresting. I don't see what you mean by area. The effect is on the tank or casing mass; for a liquid, the tank mass is presently reasonable even with hydrogen, and for a solid, you can compensate the propellant volume by the chamber pressure to keep the casing mass, knowing that the pressure influences the specific impulse slowly. The thrust doesn't depend on it, whether at liquids or solids, whose grain shape can be adapted.
Hydrogen is used in engines. Explosion hazard is its drawback. Volume is an acceptable worry, cumbersome at pumps essentially. All other propellants are dense enough, nobody cares. Throw away all books that claim something else. Propellants are not explosives.
I use CPropepShell, but Guipep is widely equivalent. A single exe file must be an installer, which will create Propellant.dat among others, which you can modify. It demands much better accuracy than 100kJ/mol on the heat of formation; 10cal/g accuracy isn't very good. A software estimate would be far too bad.
Yes, run Propep, and compare the propellants. You'll see that liquid oxygen outperforms any solid oxidizer (your numbers are off), and that all dense liquids are about as good as kerosene, hydrogen being the only one that brings significantly more specific impulse.
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I've tried Guipep again, and it's less useable. Propep alone is a DOS programme.
The best version I've had is CPropepShell, runes from W95 to Xp at least:
http://users.cybercity.dk/~dko7904/cpropepshell/cpropepshell.htm
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Your figures about the specific impulse are far off. 370s or 340s won't be achieved by solid propellants. Your sources are quite wrong, you can throw them away.
Density is widely uninteresting. I don't see what you mean by area. The effect is on the tank or casing mass; for a liquid, the tank mass is presently reasonable even with hydrogen, and for a solid, you can compensate the propellant volume by the chamber pressure to keep the casing mass, knowing that the pressure influences the specific impulse slowly. The thrust doesn't depend on it, whether at liquids or solids, whose grain shape can be adapted.
Hydrogen is used in engines. Explosion hazard is its drawback. Volume is an acceptable worry, cumbersome at pumps essentially. All other propellants are dense enough, nobody cares. Throw away all books that claim something else. Propellants are not explosives.
I use CPropepShell, but Guipep is widely equivalent. A single exe file must be an installer, which will create Propellant.dat among others, which you can modify. It demands much better accuracy than 100kJ/mol on the heat of formation; 10cal/g accuracy isn't very good. A software estimate would be far too bad.
Yes, run Propep, and compare the propellants. You'll see that liquid oxygen outperforms any solid oxidizer (your numbers are off), and that all dense liquids are about as good as kerosene, hydrogen being the only one that brings significantly more specific impulse.
Solid propellants in the 300s is possible, these can be easily achieved by a huge list of exotic fuels such as berylium hydride and AP can give 310, aluminum hydride and ADN can give 298, etc. Recent advances on ADN formulation showed that 70%ADN 20%GAP and 10% Aluminum powder could give specific impulse of 327s, 3:1:1 of the same ingredients will give 335s, change it to aluminum hydride and it will be around 350, and if you change ADN to HNF it will punch another 5s. making it near 360s. Polynitrogen materials chould achieve as high as 500s. Density does matter obviously, would you rather choose a density of 1.1 or 1.5 if given the same specific impulse? Obviously 1.5 since more propellant mass could increase the payload by a lot. Wingborg et al. (2005) have reported specific/density impulse of ADN/water/fuel as being 10 per cent and 60 per cent higher than for hydrazine, respectively
http://cdn.intechopen.com/pdfs-wm/13473.pdf
http://arc.aiaa.org/doi/abs/10.2514/3.23911?journalCode=jpp
http://www.jatm.com.br/papers/vol1_n2/JATMv1n2_p153-160_ADN-The_new_oxidizer_around_the_corner_for_an_environmentally_friendly_smokeless_propellant.pdf
Ill try download the Cpropshell now.
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Yes, run CPropepshell, and check the figures. They are brutally wrong. If papers claim that, read different ones.
Density matters little because we can build tanks bigger.
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Yes, run CPropepshell, and check the figures. They are brutally wrong. If papers claim that, read different ones.
Here is the result. ADN is not in my ingredients so unfortunately I can use it, I used the another oxidizer of similar or slightly lower performance (HAN) instead of it and here is the results. Solid propellant based on ADN/HNF and AlH3 can out-efficient some of the most common liquid propellants such as O2/RP1 and N2O4/N2H4, BeH2 is there just to show what solids can do.
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi59.tinypic.com%2Fopbbkk.jpg&hash=5306cf1b59a0cf0d716eddcaea823b5603d25692)
Of course, no solid propellant except polynitrogen materials can beat O2/H2 for now.
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You figures are wrong. To begin with, oxygen and kerosene outperform tetroxide and hydrazine, so the whole graphics is probably wrong. Bad proportions maybe. I can't imagine neither how to obtain only 300s from oxygen and hydrogen: engines get 420s even at a first stage, and 465s at a last stage.
Then, you should tell what are the pressures in the chamber and at the exhaust. Nor can you take the same chamber pressure for a solid, which translates into a heavy casing, and for liquids, which just take pumps. The RD-180 runs at 258 bar with light tanks, while the highest pressure I know for solids it 95 bar at Vega.
And of course, you shouldn't mention beryllium in any propellant, as this gives a very bad impression.
Even projected octaazacubane wouldn't beat oxygen and hydrogen, not even get near to it. It would outperform oxygen and cubane a little bit - if any useable - which exceed RP-1 by a dozen seconds.
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This is not my figures, its from PROPEP code as I already stated. APCP is not 190s, its in the 240s, and Hydrazine propellants are in the 300s. The PROPEP code under-estimate all propellant formulations by around 25%
Even projected octaazacubane wouldn't beat oxygen and hydrogen, not even get near to it.
Actually O2/H2 wont even get near to polynitrogen materials. polynitrogen materials will definately be much more efficient than O2/H2, first because polynitrogen materials is probably around 50 times more dense than H2, second, its specific impulse could achieve 500 easily.
http://link.springer.com/article/10.1007%2Fs10573-010-0020-x
The calculation is shown in this article, the high combustion temperature of polynitrogen materials could achieve nothing else ever could and therefore expand the gas very well.
The high density matters and is shown in this calculation.
http://www.sciencemadness.org/talk/viewthread.php?tid=29786
Normally small % increase in specific impulse can add much more % in payload or range. AlH3 can give around 10% more speicific impulse. However because Aluminum powder's density is 2.7 and aluminum hydride's density is only 1.4, the apogee of the calculated rocket's apogee only increased by 14% and the burn-out velocity by 8.2%
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Well then, you misuse Propep. It's accurate to better than 1%. Unsurprisingly, since many rockets have succeeded thanks to it.
All your results, all your claims are against experimental evidence, against well-established knowledge, against consensus.
One paper you cite gives a 200s range "estimate", that's nonsense, and relies on absolutely nothing. Worse, such compounds haven't been tried - nor even synthesized.
On the other link, you cite yourself. Congratulations. This won't convince me of anything, except that you should better search elsewhere the confirmation - or not - that your results make sense.
To be clear: all your results are wrong. Your figures, your assumptions, your claims.
I suggest that you first learn about rocketry, learn to use properly the software like CPropepShell, until you get some results that are compatible with the well-established ones, and only then, try to see if you may be right sometimes against the standard knowledge.
Don't hold to your wrong opinions.
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You clearly did not read the paper did you? They have shown the bond enthapies and why it could achieve such a high specific impulse. The combustion temperature could be as high as 5000.
I sited my self where I've sited many other sources, you should go read them. Do you have any sources which says hydrazine could out-perform formulations of ADN/HNF with an energetic binder such as GAP/NIMMO and an azide or hydride fuel such as AlH3 or N2H5N3?
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A computed heat of formation is worth zero. I don't need to read such a paper.
Any paper claiming 500s from nitrogen is meaningless, not worth reading.
You should distinguish between fiction and science among all these "papers", and between desired and possible.
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A computed heat of formation is worth zero. I don't need to read such a paper.
Any paper claiming 500s from nitrogen is meaningless, not worth reading.
You should distinguish between fiction and science among all these "papers", and between desired and possible.
Are you seriously saying heat of formation of polynitrogen compounds is worth zero? what do you use to calculate? toys like avorgrado? Have a look at this video then, how do you think it even explodes if nitrogenous compounds does not have positive heat of formation?
http://www.youtube.com/watch?v=Txa0fgIwiLA
This is azobistetrazole, N2(CN4)2