LiveJournal Brains: Liquid VS Gaseous Hydrogen...

[seawasp]

Anyone out there have pointers to a good reference on the physical parameters of the two states, assuming near-same temperatures and pressures (as you'd find in a tank that had some liquid H2 in it with gaseous H2 above)? I'm interested in physical, electromagnetic, etc., parameters and any differences. Some I can find easily (density, for instance), others not quite so much. I know METALLIC hydrogen has some drastically different properties but I don't know if that's the case for liquid VS gas.

Comments

[seawasp]

It definitely can. NASA has very large tanks of LH which have a gas-filled void space at the top depending on how much of the LH has been used, or boiled off (which it is always doing).

[qinshihuangdi.livejournal.com]

There are certainly tables in the Journals, the problem is finding them if you are not familiar with them and do not have a subscription.

I'd think the Seawasp would need to be pretty fortunate for there to be a single person studying and publishing on all of this. It strikes me as something that a lot of different people would have parts of what he is after.

[seawasp]

It definitely can. NASA has very large tanks of LH which have a gas-filled void space at the top depending on how much of the LH has been used, or boiled off (which it is always doing).

Unfortunately, that document doesn't cover any of the more interesting electromagnetic properties, etc.

[qinshihuangdi.livejournal.com]

If a liquid does not entirely fill the volume of its container, you will see some some of it boiling off until certain thermodynamic criteria are met. I cannot think of how the boiling point alone would be enough to significantly alter this. Even if hydrogen is hazardous and a pain to deal with, I'd think it'd be at least feasible to have liquid/vapor mixes. Imagine an insulated container with a liquid/vapor mix at the boiling point for the pressure such that there is not enough thermal energy to supply the heat of vaporization for all of the hydrogen.

[qinshihuangdi.livejournal.com]

Have you tried looking at the MSDS sheets for the liquid and the gas? The first thing that came to mind was to look in the back of my thermodynamics text for the gas tables. However, most of the stuff in the one closest to hand seems either too basic and brief or too esotaric. I don't know what kind of gas/vapour/liquid tables the CRC handbook has.

[kengr]

Well, off the top of my head, from an *old* article in Analog on the fun NASA had learning to handle liquid hydrogen (The Bugs That Live at -417° (I may have the temp wrong) was a cover article back in the 1960s some time) a big consideration is the ratio of ortho to para hydrogen molecules in the liquid.

As I recall one has the spins align in the same direction, the other has them in the opposite directions. The energy from transitioning from the higher to lower energy state is enough to boil the LH2 if there's a significant amount of the higher energy form present.

Apparently they have to run the LH2 thru a catalyst bed to force the transition while they are liquefying it.

ps. last I heard we haven't been able to confirm anything about metallic hydrogen. It *may* have been created in some high pressure setups, but wasn't stable in them.

[qhudspeth.livejournal.com]

I'd recommend talking to any of the principle investigators at the University of Florida's Microkelvin lab (http://www.phys.ufl.edu/~mkelvin/2/ContactIndex.html). They are very knowledgeable and agreeable people, any of which could point you to the right sources or possibly tell you what you need to know off the top of their heads. Try Mark Meisel or Yasu Takano first, I think.

Q

[seawasp]

I believe they may already be on our contact list for this subject area; I was hoping to just find a reference rather than have to ask them directly, but perhaps that's the best route. Thanks!