Abstract: The wicks are the power component of the loop heat pipes, and the pore size of the wick determines the evaporation heat transfer and capillary force that the wick can provide. Therefore, in order to analyze the influence of the pore size of the wicks on the loop heat pipes, the cylindrical microchannel thin film evaporation model was established by using the augmented Young-Laplace formula and the theory of energy conservation, and the theory was applied to the performance analysis of the loop heat pipe evaporator. At the same time, in order to obtain the experimental data of the effect of wicks pore size on the performance of loop heat pipes, two copper-propylene loop heat pipes with different wicks pore sizes were prepared, and their heat transfer performance was tested under vacuum environment under the heating load from 10 to 30W. Combined with the experimental data and the above model, the loop heat pipe is analyzed, and the results show that the heat transfer performance of the evaporator is affected by the heat transfer quantity and heat transfer coefficient of the wick, and the growth rate of the evaporative heat transfer coefficient slows down with the increase of the heating load, and the heat transfer performance of the evaporator deteriorates when the heating load exceeds the critical heat flux.

Key words: loop heat pipes, evaporator, evaporative, thin film evaporation, wick