Experimental and numerical results in closed annular space heat transfer at low temperature

Abstract As part of the Laser Megajoule Facility for cryogenic targets, we have studied the heat transfer at low temperature (6 K T K ) between two coaxial cylinders whose annular space was filled with helium gas. We have built a cryostat and carried out many experiments on the conduction/convection heat transfer transition in closed annular spaces. We found that gas convection begins as soon as a temperature difference exists between the two cylinders even at low pressures. Convection can generate azimuthal temperature gradients because of the non-uniform local heat transfer. The experiment is compared to numerical simulations.