Jim Grant Forum Moderator 119 Posts
Re: Comparing Heat Transfer Efficiencies10 February 2009 at 1:29pm
If one calculates the heat transfer coefficient at the same mass flow through a fixed geometry, the hydrogen heat transfer coefficient will be much greater. If, however, one calculates at the same velocity the hydrogen coefficient will be about 2x the air coefficient. The Pr numbers for both fluids are similar (near 0.7). However, the thermal conductivity and heat capacity at similar pressures are much higher for hydrogen.