Los Alamos and Penn State developing a new solid rocket fuel

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goose_in_co

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Saw this on the Yahoo news crawler. Interesting that it would make the list there.
They do not mention any formulas other than to state that it is safer than traditional propellants because they separate the fuel from the oxidizer. Sounds like another Hybrid rocket propellant to me, but I couldn't make anything out from the video, other than they were having fun launching rockets from a nicely built tower launcher with a lot of high speed cameras around. URL is here:

https://phys.org/news/2014-10-rocket-propellant-motor-high-safety.html
 
The article has nothing to do with the photo. The article describes a nano-aluminum water rocket motor like the one in the video below.

[YOUTUBE]PqzQ3aXZeNk[/YOUTUBE]

The photo in the above article is of a rocket with a "novel" LANL hybrid motor that is shown in video below.

[YOUTUBE]wwEVFVfvA50[/YOUTUBE]

The video is quite careful scripted not to state anything technical, so how much is smoke and mirrors and how much is real remains to be seen. The motor appears to be a hybrid rocket motor done in reverse: you are lead to believe the energetic fuel is a liquid and the oxidizer is a solid. Nothing else is said in the video.

Comparing the "new" LANL hybrid motor's higher thrust and efficiency to a solid rocket motor is somewhat self-serving as hybrids typically have higher specific impulse than solids while the thrust depends on the propellant consumption rate which is a design parameter of both hybrids and solids.

https://www.lanl.gov/quarterly/q_sum...explosives.pdf may give some insight into what they are doing.

https://www.sciencemadness.org/talk/v...d.php?tid=3431 discusses a couple of the compounds they mention in the article. Maybe they used or maybe not.

The propulsion system makes little sense to me as a physical chemist. I could see using NOX as a liquid oxidizer and a solid amine as a hypergolic fuel in a hybrid, but energetic liquid fuels are somewhat uncommon as are efficient solid oxidizers. My curiosity is peaked so I will continue a little research on the group.

Bob
 
I'm not sure why they would use heavy water, since the Isp usually scales inversely with the square root of the mean molecular weight of the fragments. H is twice as light as D.
 
What about HAN? I just did a google search and it says that it can be a solid oxidizer.
I doubt it, but it is a possibly. The mention safety but HAN is also an energetic monopropellant, so as a solid oxidizer in a hybrid under certain circumstances it could go off all by itself whether or not the fuel is flowing....which is definitely not safe.....

I'm not sure why they would use heavy water, since the Isp usually scales inversely with the square root of the mean molecular weight of the fragments. H is twice as light as D.
Because they're LANL, and they're doing kinetic studies. The isotope effect is an important cross-check of their reaction rate constants and mechanisms which were the goals of their study.

Bob
 
I'm not sure why they would use heavy water, since the Isp usually scales inversely with the square root of the mean molecular weight of the fragments. H is twice as light as D.

Not only that, but D2O is considerably more expensive than H2O. In any case this is a little bit off the real topic as to what the new hybrid is really using.
 
The poorly written article referenced above and the first video is about a nano-aluminum/water slurry (ALICE?) solid rocket motor. H2O and D2O were used to get fundamental kinetic information on the reaction rates and mechanisms.

The photo accompanying the article and the second video is from a different project that the LANL group is pursuing which apparently is a reverse hybrid motor.

Two totally different LANL projects.

Bob
 
You nailed it David. From the description in the patent, it is not really a hybrid as the energetic fuel is really a monopropellant, but rather a solid rocket motor with an afterburner....

Bob
 
You nailed it David. From the description in the patent, it is not really a hybrid as the energetic fuel is really a monopropellant, but rather a solid rocket motor with an afterburner....

Bob

Did you notice that the propellant chamber pressure was much higher than the oxidizer chamber? I expected some pressure drop across the injecter but dropping from 800psi to 200psi seems excessive.
 
Did you notice that the propellant chamber pressure was much higher than the oxidizer chamber? I expected some pressure drop across the injecter but dropping from 800psi to 200psi seems excessive.
Yes I did, and it just adds to the bafflement. I don't see how safety is enhance by this design as the energetic oxygen deficient monopropellant fuel is easier to ignite than APCP, and once ignited, the motor goes on full. I also don't see how you get a performance gain over a simple SRM due to the lower chamber pressure. I believe the supersonic expansion of the monopropellant exhaust is done to make the monopropellant mass flow independent of the downstream (afterburner) chamber pressure.

ORD_GQM-163A_Coyote_Cutaway_lg.jpg


The energetic solid monopropellant fuel concept is used in some supersonic ramjet target missiles like the GQM-163 Coyote shown above where oxygen from the ram air is used to combust the hydrocarbons generated by the solid monopropellant decomposition but the ram jet is simply incorporated into the airframe without mass penalty and eliminates the need to carry the oxidizer. I would also believe you loose any mass advantage when you have dual combustion chamber and carry the oxidizer in a rocket motor. Here is another reference.

So IMO the LANL group has taken a proven ramjet concept and turned it into a rocket. Novel perhaps but not particularly useful, and negating any of the advantages that you had when used as a ramjet........because they now have to carry the heavy oxidizer within the motor......

Bob
 
From what I understand. It's a pure solid hybrid rocket motor. Not a liquid solid hybrid. The fuel (triaminoguanidinium azotetrazolate) is in the top and the oxidizer (AP) is in the bottom.
NewMotor.jpg

The goal is to gain a higher ISP by using energetic fuels that would be to sensitive if mixed in a HTPB binder together. So there held separate before there combusted.
With the goal of eventually using ammonium dinitramide and aluminum hydride which is an HE (scary stuff) when mixed.

What I still don't understand is how the top solid fuel moves into the bottom chamber when ignited. Apparently there is some sort of orifice. (Inner Nozzle) Could be
the bernoulli effect of the gasses rushing out of the main nozzle. But that's a serious wild ass guess. Then what's the graphite spacer for in the top chamber????
Could it be some sort of plunger???? This is some awesome cool stuff!
 
I was wondering the same thing (would a mechanically driven plunger work?). Bob's post mentioning N2O dry ice got me thinking of a hybrid where the combustion chamber is a ported cylinder of N2O dry ice and then extrude solid parafin through a orifice by a screw driven plunger.

Bob, if you are reading this could this work?
 
From what I understand. It's a pure solid hybrid rocket motor. Not a liquid solid hybrid. The fuel (triaminoguanidinium azotetrazolate) is in the top and the oxidizer (AP) is in the bottom.
View attachment 188952

The goal is to gain a higher ISP by using energetic fuels that would be to sensitive if mixed in a HTPB binder together. So there held separate before there combusted.
With the goal of eventually using ammonium dinitramide and aluminum hydride which is an HE (scary stuff) when mixed.

What I still don't understand is how the top solid fuel moves into the bottom chamber when ignited. Apparently there is some sort of orifice. (Inner Nozzle) Could be
the bernoulli effect of the gasses rushing out of the main nozzle. But that's a serious wild ass guess. Then what's the graphite spacer for in the top chamber????
Could it be some sort of plunger???? This is some awesome cool stuff!
UhClem got it right as the patent fully describes the motor operation. https://www.rocketryforum.com/showt...g-a-new-solid-rocket-fuel&p=778631#post778631 I'm not sure why the description in the video is cagey and a bit deceptive since a provisional patent was previously granted.

IMO the correct description of the LANL hybrd motor is a SRM with an afterburner. The fuel described in the patent is not actually inert, it is a high nitrogen content energetic monopropellant, albeit oxygen deficient. While it does not need the AP to generate propulsive force, the AP chamber is the functional equivalent of an afterburner on a jet engine where extra energy is provided to the hot propellant gas. The hot fuel rich propellant gas generate in the primary combustion chamber is oxidized and further heated by combustion of the hydrocarbon fuel fragments in a second lower pressure combustion chamber.

I'm not sure how much of an apples to oranges comparison was presented in the video as no quantitative information was presented for the performance of the LANL hybrid and the APCP motor it was compared to. The comparison SRM was certainly not a V-Max or Warp-9 propellant which probably would have generated a higher acceleration and velocity than the LANL hybrid.

High nitrogen content propellants/explosives have been a topic of interest for a long time. Our company has synthesized several novel variations of them for Uncle Sam in the recent past for use as propellant additives, low signature explosives, thermobaric weapons, gas generators, etc. Very interesting chemistry.


I was wondering the same thing (would a mechanically driven plunger work?). Bob's post mentioning N2O dry ice got me thinking of a hybrid where the combustion chamber is a ported cylinder of N2O dry ice and then extrude solid parafin through a orifice by a screw driven plunger.

Bob, if you are reading this could this work?

What I mentioned was ALICE, nano-aluminum-ice (frozen water not dry ice). It's premixed as a slurry in a SRM, and after the proper analysis is performed it's a really poor propellant system for a rocket due to the trivial fraction of the propellant mass that produces thrust.

Dry ice would to extinguish the combustion in a nitrous hybrid so I don't see how it could work.

Bob
 
Part of what I got from the video was the idea that the motors, despite the use of higher energetic materials, would be safer to handle, transport, store, and use.
 
Bob, My idea was N2O dry ice in the combustion chamber NOT CO2 dry ice.
You mean solid N2O? That would require maintaining the combustion chamber temperature below ~-90 C during and after filling which would be an almost impossible task in a small rocket motor. And after ignition, I believe the energy input would be so high from combustion, that the solid NO2 would vaporize uncontrollably, and overpressurize the chamber.

Bob
 
Bob I get the second point but solid N2O should behave like dry ice (similar properties). CO2 dry ice stays solid for long periods relative to the time is takes to fill a hybrid tank.
 
This is from a related patent from CTI:
https://www.google.com/patents/US7022196

BACKGROUND TO THE INVENTION
...
Solid propulsion systems could provide very high specific impulse by utilizing high performance oxidizers such as ADN, HAP, HAN, HNF, NP and the like. Many of these oxidizers offer significant gains on performance, reduced or low toxicity and have desirable exhaust signature characteristics, when compared to propulsion systems using traditional solid oxidizers. However, many of these oxidizers suffer from varying degrees and forms of instability, such as photo sensitivity, shock, friction and impact sensitivity, decomposition in the presence of moisture, sensitivity to pH and incompatibility (such as hypergolic reaction) to other propellant materials. A typical example of incompatibility is reaction between HNF and curing agents used in solid propellant binder systems such as HTPB and GAP. Many difficulties have been encountered incorporating the oxidizers into propellant systems, and solutions to particular storage and stability problems often result in compromising the theoretical performance potential. For example, current techniques to synthesize HNF still produce particles with length to diameter ratios of 2:1 to 3:1 with significant variation from the mean. This seriously impacts formulation rheology and can prevent achievement of optimum solids loading, as well as aggravating friction sensitivity during mixing and casting operations.

Storing the oxidizer separately in the motor offers the ability to avoid compatibility issues between oxidizers and common solid propellant system components. Separate storage of solid and semi-solid oxidizers and expulsion systems have been proposed and demonstrated in the past. Some of the difficulties in these approaches include flow stability, concentration and distribution of oxidizer solids in carrier agents, pressurization and piping system requirements, specialized control valves and system integration.


On a mostly unrelated note, though it refers to the above patent, I'm sometimes surprised what kind of stuff can actually get patented:
https://www.google.com/patents/US8683933 (rocket related, fittingly published on April 1st)
https://www.google.com/patents/US8403402 (not rocket related, but from the same guy)

Reinhard
 
Part of what I got from the video was the idea that the motors, despite the use of higher energetic materials, would be safer to handle, transport, store, and use.
That is claimed, but without any justification or evidence.

The patent states, "Triaminoguanidinium azotetrazolate is a bright yellow, needle-like crystalline solid having a theoretical maximum density of 1.60 g/cm3, a decomposition temperature of 195 degrees Celsius, and a heat of formation of +257 kcal/mol."

So if this statement in the patent is correct, then the compound aka TAGZT (shown below) it is not safer than APCP and many other solid propellants, as the ignition temperature of APCP (and BP motors) is significantly higher than 195 C.

I can say is that every time I have shipped various azotetrazolates that our company synthesized for various government agencies, the materials are shipped under a DOT-SP 8451 Special Permit in a Steel Pipe that can contain the explosion if it goes off. At a minimum it is a 1.3 explosive and possibly a 1.2 or even 1.1 in large quantity.

US20140109551A1-20140424-C00001.png


This stuff would rather be N2, H2, and C and will do so in a heartbeat if given the opportunity........

Bob
 
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