Analysis of a propylene loop heat pipe in steady state and transient mode

LHP is a passive heat transport device that uses capillary forces to circulate a two-phase working fluid. It consists of a heat-accepting evaporator, heat rejecting condenser, fluid reservoir and a pipe network to connect the components. Internal to the evaporator there is a porous wick, which provides capillary pumping of the fluid in the loop. An innovative LHP will be used in the Alpha Magnetic Spectrometer (the so-called ‘AMS-02’ project for the International Space Station – http://hpl3tri1.cern.ch/) as the core thermal control system in order to control the temperature of a set of cryo-coolers by means of a direct condensing radiator. In this paper this LHP will be analyzed and an analytic model of the operating temperature carried out. By implementing a numerical model (SINDA/FLUINT) the thermophysical properties in the loop were obtained for every time. These results are then compared with the data obtained by other numerical codes coming from the heat pipe German company OHB and Spanish IberESPACIO. Finally a parametric analysis was partially carried out to understand the influence of critical parameters on the operation of LHP.