Two-dimensional mathematical model of the miniature flat plate capillary pumped loop (CPL) evaporator is presented to simulate heat and mass transfer in the capillary porous structure and heat transfer in the vapor grooves and metallic wall. The overall evaporator is solved with SIMPLE algorithm as a conjugate problem. The shape and location of vapor-liquid interface inside the wick are calculated and the influences of applied heat fluxes, liquid subcooling and metallic wall materials on the evaporator performances are discussed in detail. The effect of heat conduction of side metallic wall on the performance of miniature flat plate CPL evaporator is also analyzed, and side wall effect heat transfer limit is introduced to estimate the heat transport capability of capillary evaporator. The conjugate model offers a numerical investigation in the explanation of the robustness of the flat plate CPL operation. (C) 2011 Elsevier B.V. All rights reserved.