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Hydrogen Cools Well, but Safety Is Crucial

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Re: Hydrogen Cools Well, but Safety Is Crucial

#11

Post by thsksbd »

foobarbecue wrote: post #10
phkahler wrote: post #9

Earlier quoted context omitted.

Nope. Hydrogen is not just flammable, the article tells you it is EXPLOSIVE at concentration of 4 percent to 74 percent in air. If the Hindenburg was a hydrogen-air mixture, it would have leveled a large portion of the area rather than just burning where it fell. I've worked in areas where they were developing hydrogen fuel cell vehicles at major auto makers. The facilities are equipped with collectors, detectors, an…

Hydrocarbon-air mixtures are also "EXPLOSIVE". See, e.g thermobaric weapons. Possibly what you're trying to say is that it's easier to get the air in? Or that it's stored under pressure?

The point is that, as scary as gasoline is, the explosive mixture is quite narrow compared to H2.

Add in a minuscule spark energy and H2 is no joke

Re: Hydrogen Cools Well, but Safety Is Crucial

#12

Post by Karellen »

> Kilmartin said one of the questions he asked when he first got into the business was “who came up with this idea? He had to be a madman.”

Kilmartin should spend more time around rocket scientists. After hearing a few tales of some of the stuff they've come up with in the name of performance - like a Hydrogen/Lithium/Fluorine(!) tripropellant engine (but you get an Isp of 542s!!!) - using Hydrogen for cooling will sound positively tame, and easily controlled.

Re: Hydrogen Cools Well, but Safety Is Crucial

#13

Post by abakker »

kylec wrote: post #4
someguydave wrote: post #3

This is why the idea of the public using hydrogen cars is kind of crazy.

Just wait until you hear about this explosive fuel called "gasoline" that is quite popular for powering cars too

ever watched someone extinguish a cigarette in gasoline? it's explosive, but in a narrow band of conditions.

Re: Hydrogen Cools Well, but Safety Is Crucial

#14

Post by glitchc »

flextheruler wrote: post #6
someguydave wrote: post #3

This is why the idea of the public using hydrogen cars is kind of crazy.

Right since we haven’t already used an equal or even more so flammable substance for the past century As far as I’m aware gasoline ignites at much lower mixtures of oxygen than hydrogen. The Hindenburg can’t hurt you and if it was filled with gasoline vapors instead of hydrogen, well it would never get of the ground, but it would have been more dangerous.

The Hindenburg is a largely misunderstood incident [1]. It was one of the safest airplane crashes of the century. As the balloon burned, flames and gasses vented upwards, keeping the cabin and passengers under the balloon safe. Moreover, the balloon descended slowly as the hydrogen was replaced by air. So slowly that most people got off once it was close to the ground. Out of 97 people only 35 died.

[1] https://www.history.com/news/the-hindenburg-disaster-9-surpr...

Re: Hydrogen Cools Well, but Safety Is Crucial

#15

Post by glitchc »

abakker wrote: post #13
kylec wrote: post #4

Earlier quoted context omitted.

Just wait until you hear about this explosive fuel called "gasoline" that is quite popular for powering cars too

ever watched someone extinguish a cigarette in gasoline? it's explosive, but in a narrow band of conditions.

You've been watching too many movies. MythBusters tested this. A pool of gasoline will extinguish a cigarette dropped in it every time.

Re: Hydrogen Cools Well, but Safety Is Crucial

#16

Post by MPSimmons »

Hydrogen sucks to work with, from everything I've heard. In addition to the combustion risk when oxygen is introduced, there's the fact that hydrogen molecules are tiny and like to slip through otherwise solid materials, which is annoying if you're trying to fuel a rocket, but it's eventually catastrophic for containment vessels, due to hydrogen embrittlement[1]. As tempting as it is for its benefits, I don't see it being worth the long-term risks and engineering trades.

https://en.wikipedia.org/wiki/Hydrogen_embrittlement

Re: Hydrogen Cools Well, but Safety Is Crucial

#17

Post by bell-cot »

Qwertious wrote: post #5
someguydave wrote: post #3

This is why the idea of the public using hydrogen cars is kind of crazy.

Not really - hydrogen shoots straight up into the atmosphere, whereas petrol both pools in the area and also turns to gas and mixes with air quite easily (which is why it's used as a fuel in the first place) In practice, hydrogen cars are quite safe. They're just not worth the cost in infrastructure and lack of efficiency compared to BEVs.

> ...hydrogen shoots straight up into the atmosphere...

Two words: Attached Garage

Re: Hydrogen Cools Well, but Safety Is Crucial

#18

Post by MPSimmons »

glitchc wrote: post #15
abakker wrote: post #13

Earlier quoted context omitted.

ever watched someone extinguish a cigarette in gasoline? it's explosive, but in a narrow band of conditions.

You've been watching too many movies. MythBusters tested this. A pool of gasoline will extinguish a cigarette dropped in it every time.

I think you and the comment you replied to are agreeing.

Re: Hydrogen Cools Well, but Safety Is Crucial

#19

Post by Tuna-Fish »

Karellen wrote: post #12

> Kilmartin said one of the questions he asked when he first got into the business was “who came up with this idea? He had to be a madman.” Kilmartin should spend more time around rocket scientists. After hearing a few tales of some of the stuff they've come up with in the name of performance - like a Hydrogen/Lithium/Fluorine(!) tripropellant engine (but you get an Isp of 542s!!!) - using Hydrogen for cooling will s…

Rocket science as a field moved out of exotic energetic fuels by the end of the 90's, because the juice wasn't worth the squeeze, and there is currently an ongoing industry-wide exodus from hydrogen to methane for the same reason.

Getting the peak of performance sounds cool when you ignore costs, but in the real world with limited budgets, building a rocket twice as large is easily worth it if it means you never have to touch liquid hydrogen.

Re: Hydrogen Cools Well, but Safety Is Crucial

#20

Post by abakker »

glitchc wrote: post #15
abakker wrote: post #13

Earlier quoted context omitted.

ever watched someone extinguish a cigarette in gasoline? it's explosive, but in a narrow band of conditions.

You've been watching too many movies. MythBusters tested this. A pool of gasoline will extinguish a cigarette dropped in it every time.

I was not clear - I agree with you. I was saying that gasoline might be explosive, but it is not likely to happen. it is remarkably tolerant of heat/spark at STP conditions.
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