Rocket Fuel Contributes To Apartment Fire

This should be in the FAQ

Reply to
Jerry Irvine
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I assume like the others reported in the story, the rocketeer lost everything in the fire. Do you know his insurance status? Is there anything we as a rocket community can do for him and the other folks who lost so much in this fire?

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

I found out he wasn't smart enough to have renter's insurance. He literally spent every penny of his spare cash on rocketry.

If you want to help the other victims of the fire I would contact the Red Cross in Des Moines, IA.

Brian Elfert

Reply to
Brian Elfert

Ouch. I see this so often. The people that need it most seem to be the least likely to have it in the first place.

Thanks for the pointer.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

That's great! :-)

Eldred

Reply to
EldredP

I can't remember where I stole\\\\\found this. But a search shows a Gary Heston using it as his .sig back in 1991.

For someone like Ashcroft, you'd need cases and daily doses.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

Say, you could even insulate the combustion chamber with a material like paper, plastic, or rubber, that would decompose and provide fuel to further increase Isp!

;-)

Mike D.

Reply to
Mike Dennett

Hi Anthony, thanks for your reply.

I selected the 5 gallon figure for illustration purposes only as it seemed to be a reasonable amount, as opposed to 0.5 or 50 gallons. I have no information on the actual inventory of N2O present. You are certainly correct that the adiabatic flame temperature increases when using N2O as the oxidizer. This will have an effect similar to enrichment of air with oxygen in addition to the actual enrichment with oxygen due to N2O decomposition. Bouyancy-aided flame spreading rates are certainly affected by oxygen concentration as seen in this report:

However flame spreading is a heat and mass diffusion-controlled process that responds proportionally to increases in flame temperature, not an exponential rate dependence (see Figure 2.17 for instance).

I think most fires would need to progress substantially before they would heat a stored N2O bottle enough to rupture it, in which case the oxidizer addition would be made to an already relatively large fire, unless the fire was actually started next to the tank. I do not know what the design of this particular bottle was, however it is common for compressed gas cylinders designed to contain a large "liquid" inventory (e.g. ethylene) to be equipped with a rupture disk or relief valve to prevent an energetic disassembly. A rupture disk would normally allow an initial large puff of vapor to be vented that would quickly drop the tank pressure and temperature, followed by a nearly constant flow rate due to boiling of the liquid. In this case the venting rate is dictated by the heat transfer rate to the bottle - similar to boiling water on a fire in a paper cup. I therefore would expect flame acceleration effects to be localized and the overall flame spreading rate through the structure substantially unaffected by the addition of N2O to the fire at that point in its progress. If the escaping N2O were instead dispersed in the air in the structure, the flame temperature of the wood/carpet/plastic/paper would not be substantially higher than with air alone, so again the overall flame spreading rate would not be materially affected.

In the case of wholesale rupture of the N2O bottle, the time of an enriched N2O atmosphere would also be pretty short. Most structures cannot withstand more than a couple psi or so of overpressure (150 mph hurricane winds only have a 0.4 psi dynamic pressure, for instance), which is not enough to really affect combustion reaction rates themselves, particularly for diffusion flames - although the shattering effect on the structure could certainly make more fuel available to the fire. That could occur with other compressed gases as well (e.g. propane) and is not unique to N2O.

I (still) conclude that the presence of a tank of N2O used by hybrid HPR enthusiasts would have little (not NO effect, but little) to do with the final severity of fire damage (how much was burned, $$$ loss) in most cases.

Experiment, anyone?

Brad Hitch

Reply to
Brad Hitch

Excellent explanation, Brad. I actually understood it completely!

thanks, steve

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