3D Numerical Study For Heat And Mass Transfer Of The Evaporator In A Flat Miniature Loop Heat Pipe

In the field of electronics cooling with high heating flux and spacecraft thermal control,the traditional single-phase radiator can not meet the critical requirement.Loop heat pipe(LHP)is a passive two-phase heat transfer device,which has many advantages including zero-power consumption,flexible transport lines,high heat transfer capacity.As the core component of LHP system,evaporator provides power for whole system,and the performance of evaporator determines the performance of LHP system to a great extent.Distinguish from modeling for evaporation heat transfer unit consisting of a single channel and capillary wick,in this paper,a complete three-dimensional model for a flat plate evaporator is established,including the wick,compensation chamber(CC),heat conduction ribs and evaporator shell.3D numerical simulation was implemented using FLUENT software.Multi-domain-coupling numerical solution is achieved by loading evaporation function at evaporation interface.On the basis of the three-dimensional model,in this paper,firstly,the effect of heat load on heat transfer and flow in the evaporator is studied,temperature distribution of evaporator,heat transfer at evaporation interface,flow and heat transfer in CC were analyzed under different heat loads.Secondly,influence of the shell material on heat transfer of evaporator is studied,heat leak and evaporator thermal resistances was analyzed.Influence of the position of reflux liquid inlet on flow and heat transfer in CC was also studied.Numerical results show that heat transfer and flow in the evaporator are the result of various heat transfer mechanisms.When heat load is matched with condensing capacity of the system,that is,when heat load is moderate,the proportion of evaporation is higher,flow and heat transfer characteristics of system is optimal.When the material with high thermal conductivity is used as shell,the average temperature of CC and evaporator thermal resistances is lower.The location of the reflux liquid inlet affects flow field distribution in CC and forms stagnant zone in different ranges.The research results have some reference value for flat plate LHP evaporator design.