Heat and mass transfer in cryogenic gas-loaded heat pipes

Physical properties of the main components of a heat pipe vary at cryogenic temperature, which significantly affects heat and mass transfer. It is shown that to attain large temperature sensitivity factors and enhanced heat transfer on the condenser surface, the condensation section of a heat pipe envelope should be made of a material with high thermal resistance in the axial direction and low thermal resistance in the radial one. In order to confirm peculiarities of cryogenic heat pipe operation, three cryogenic gas loaded heat pipes were constructed and an attempt was made to study the temperature sensitivity factor.