Abstract: A novel evaporator of miniature flat plate capillary pumped loop (CPL) is presented for application of dissipating high heat flux. Based on the structure characteristics of miniature flat plate CPL evaporator, the effect of metal side wall conduction of evaporator on the CPL work limit is analyzed. An overall numerical model for the miniature flat plate CPL evaporator is presented, which includes heat and mass transfer in the porous wick structure, liquid flow and heat transfer in the compensation cavity and heat transfer in the vapor grooves and metallic wall. The entire evaporator is solved with SIMPLE algorithm as a conjugate problem. The numerical results show that liquid evaporation takes place near the upper and left surfaces of wick structure in the evaporator. The flat plate evaporator with single aluminum wall results in lower heat transfer limit, but leads to low temperature level and good isothermal behavior of the heated surface. On the other hand, the evaporator with single stainless steel wall leads to higher heat transport capacity, but to higher temperature level of the heated surface. The evaporator with combined wall (upper wall with aluminum, side and bottom wall with stainless steel) increases heat transfer limit, and decreases temperature level and temperature gradient on the heated surface, which implies that the CPL can operate safely and cooled apparatus also can work effectively under high heat fluxes.

Key words: Capillary pumped loop, Coupling computation, Evaporator, Porous media