Threedimensional numerical simulation for heat and mass transfer of the evaporator in a flat miniature loop heat pipe

In order to analyse the heat and mass transfer of the evaporator in a flat miniature loop heat pipe, a multidomaincoupling mathematical model was developed and threedimensional numerical simulation was implemented using FLUENT software. According to the results, the evaporator heat transfer characteristics showed obvious difference at different heat loads. Evaporator temperature was not only determined by the heat load, but much affected by the two heat transfer mechanisms on the wick surface, i.e: capillary evaporation and heat conduction. Compared with high heat load (Q=120W) and low heat load (Q=40W) condition，all parts of the evaporator under medium heat load (Q=80W) condition were at lower temperature. For all of the three different heat loads, inverse heat conductions from the wick were larger than heat leak from the side walls, therefore the highesttemperature region in compensation chamber easily presented near the wick. Backflow from the condenser flowing into the evaporator formed two large eddies in compensation chamber. Such a flow characteristic is conducive to chilling wick. When the heat load added on the system matches its condensation capacity, the flow and heat transfer characteristics of the system is optimal.