Parametric analysis of steady-state operation of a CLHP

Cryogenic loop heat pipes (CLHPs) possess high pumping capability and good heat transfer performance that are important for effective and efficient cryogenic heat transport with considerable applications in space and terrestrial surroundings. Built on a previous model developed for a conventional loop heat pipe (Bai et al. [21]), this paper establishes a steady-state mathematical model for a cryogenic loop heat pipe using nitrogen as the working fluid. The modeling results are benchmarked with an experimental study and good agreement is achieved. A parametric study of the effect of heat sink temperature, parasitic heat loss, adverse elevation and heat loads applied to the secondary evaporator on the performance of the CLHP is conducted. A number of interesting phenomena are revealed through the analysis such as CLHP working in the variable conductance zone and enhanced performance of the CLHP by switching on the secondary evaporator. The detailed temperature and pressure characteristics of the CLHP are also captured that provide guidance for the system design and optimization.