Amusing Hydrogen tankage thoughts

atpollard · Sunday at 8:09 PM

infojunky said:
Does it?

I was not implying that I was the THOUGHT POLICE.

I was merely observing that your OP figure is a single data point.

A tank with 1/100 the volume of LH2 will have exactly 1/100 the volume of fuel but a different value for kg of tank per cubic meter of LH2 [and a tank of exactly 1/100 the volume of Tank plus fuel will have a different volume of LH2 and still have a different measure of kg of tank per cubic meter of tank and fuel.] The thickness of the insulation will be constant, but the surface area and volume inside the tank will change, so the ratio of tank mass to volume will change with size.
If you build a tank 100x larger than your design, the data point will change again.

So the only CONSTANT value for a dTon is based on internal fuel (which maintains a constant ratio of volume to mass ... density).

Spinward Scout · Monday at 3:47 AM

TamsinP said:
Ships carrying liquid cargoes have them too; I would imagine that aircraft with large fuel tanks would have them as well.

I don't think you can avoid it. Unless you split up the tanks into a bunch of smaller tanks. Which might make sense from a combat point of view. If you spill one small tank, it's better than getting a hole in a big tank.

Rupert · Monday at 3:47 AM

kilemall said:
Still would be prohibitive to go gaseous state as now you have to push/jump all that hull that carries and protects the fuel.

Playing round with various design systems that do care about mass as well as volume (FF&S and GURPS Vehicles, mainly) has shown me that even with liguid hydrogen the low density can be a problem - despite its high energy density it can be worse than hydrocarbons because of the extra volume liquid hydrogen tanks require, and the bigger and heavier hulls required to hold those tanks, and the bigger engines, etc. required to move them, etc. - if a design is tight this can snowball quite seriously.

Spinward Scout · Monday at 4:01 AM

Spinward Flow said:
Try 1 : 848 (according to the US Department of Energy) on for size and then ask yourself if the refrigeration equipment is "worth it" so you can have SMALLER hydrogen tanks. Wikipedia lists the expansion ratio at 1:850.

Wow! What a difference. So what happens when you get a fuel hit in combat? I've never looked that up.

L-Hyd flowing all over the ship is dangerous. Your VACC Suit isn't going to do much if a wave of liquid hydrogen washes over you. Although it might evaporate pretty fast.

kilemall · Monday at 5:02 AM

Spinward Scout said:
Wow! What a difference. So what happens when you get a fuel hit in combat? I've never looked that up.

L-Hyd flowing all over the ship is dangerous. Your VACC Suit isn't going to do much if a wave of liquid hydrogen washes over you. Although it might evaporate pretty fast.

Doesn’t really do anything per tables. Of course the fire/explosion risk should be mitigated by going to vacuum precautionary.

Ever since a deep dive into HG and the radioactive shielding property of LH, I’ve assumed the bulk of tanks wrap around near the surface and blow out to space when damaged. I’ve also included them into rad hits, with the effect being fuel going unrefined.

Spinward Flow · Monday at 7:13 AM

Spinward Scout said:
Wow! What a difference.

Hence why I was so ... incredulous ... that you even proffered the option.

Spinward Scout said:
So what happens when you get a fuel hit in combat? I've never looked that up.

You get a surface explosion hull rupture and a portion of your fuel load (minimum 10 tons) gets vented out into space, where it is lost (just like with most other forms of explosive decompression).

I was under the impression that this type of result was self-explanatory.

Ekofisk · Monday at 11:21 AM

Spinward Scout said:
So what happens when you get a fuel hit in combat?

This?
Consider this another vote for precautionary depressurization.

Spinward Scout · Tuesday at 11:46 PM

Ekofisk said:
This?
Consider this another vote for precautionary depressurization.

I like Spinward Flow's explanation. Not dealing with steam and flame would be much better.

Spinward Flow said:
Hence why I was so ... incredulous ... that you even proffered the option.

You get a surface explosion hull rupture and a portion of your fuel load (minimum 10 tons) gets vented out into space, where it is lost (just like with most other forms of explosive decompression).

I was under the impression that this type of result was self-explanatory.

Yeah, that's what I get for posting around 4am.

Ekofisk · 2024-11-20T06:36:48-0600

Hydrogen explosions here. Nice one starts at 4:48 in.
The Battlerider game has a critical that covers this:
"Ship Explodes: Liquid hydrogen and oxygen escape from shattered storage tanks, combine in the interior spaces of the ship, and explode, setting off a chain reaction with the ship's ordnance and power plant. The vessel is completely destroyed. Replace the ship counter with a White Out-2 marker."

Has the makings of "bad day" written all over it.

Condottiere · 2024-11-20T09:12:03-0600

Armoured bulkhead internally, blow out panels externally.

Spinward Scout · 2024-11-21T01:49:19-0600

atpollard said:
I was not implying that I was the THOUGHT POLICE.

Zhodani spy?

Condottiere · 2024-11-21T03:06:58-0600

Media influencer.

Amusing Hydrogen tankage thoughts

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