Heat Transfer Media

Reliable sources say a stream of helium gas is
a very good coolant. Why is that? As a monatomic
gas it has no vibrational modes, so it should have
a low specific heat. But a high specific heat is
not necessary for a good coolant. It's the heat
transfer rate that matters, not the amount of
heat-in-transit. I'm guessing the low molecular
weight contributes by increasing particle speed
for a given amount of energy, hence increasing
heat transfer rate.
Along the same lines, why are beryllium oxide and
diamond excellent heat conductors. I'm guessing
in the case of BeO, it's the same as helium except
the atoms are constrained within the ceramic lattice.
It's like solid helium.
Diamond is more of a puzzle to me. I'd guess it's
a really tight lattice, so it's not as lossy a
lattice as a looser one like water ice. It rapidly
and efficiently transmits heat like a good bell metal
rapidly and efficiently transmits acoustic waves.
Am I way off base here, or are these reasonable
layman's models for the heat-transfer properties
of these materials? If wrong in certain aspects,
can they be modified or fixed to bring them more
in line with current understanding?
Reply to
Mark Thorson
Loading thread data ...

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.