I am wondering how the thermal conductivity of a gas depends on the pressure, at very high pressures. I tried using google but did not find anything
useful. I don't need something exact, just "back of the envelope", i.e. is it linearly, sqrt dependent etc.
Thanksgsd - 9-3-2011 at 06:37
Try this book:
The Properties of Gases and Liquids, Fifth Edition
by: Bruce E. Poling, John M. Prausnitz, John P. O'Connell
I think in Chapter 10 you will find what you are looking.
Hope this helps.
gsdm1tanker78 - 9-3-2011 at 06:57
You can use the formulas given in this web page and plug in different values of pressure; leaving the gas composition and its coefficient of thermal
conductivity constant. Use at least 3 or 4 different values and graph the results. This should give you a back-of-the-envelope idea as to whether it's
linear or otherwise.
CO2 lasers usually employ helium in the gas mix to aid in the removal of heat from the cavity at low pressures. You might also try using this in your
search and see if it takes you anywhere.
On the top of my head, I'd imagine that as pressure increases, so too would conductivity as there are more atoms per unit of volume so it'd be easier
for molecular movement to transmit through the material. Are we talking metallic hydrogen pressures?
gregxy - 10-3-2011 at 10:03
Actually the thermal conductivity is roughly constant with pressure.
The number of atoms to transfer heat goes up, but the
mean-free-path goes down.
