Heat Transfer Enhancement in Two-Phase Systems with Capillary Pumps

Heat transfer in two-phase loops with capillary transfer of a heat carrier is due to the mass transfer of a circulating heat carrier in the form of vapor or liquid. Therefore, the heat transfer capacity (heat flux or the product of heat flux by heat transfer length) of such systems is governed by the hydrodynamics of phases. The influence of structural, hydraulic, and thermophysical properties of capillary structures used as capillary pumps in two-phase systems for temperature control (loop heat pipes) on their heat transfer capacity has been analyzed. Ways to improve the heat transfer capacity of loop heat pipes using anisotropic capillary structures through a decrease in pore size toward an evaporation zone have been determined. Methods providing the efficiency of loop heat pipes and a technique for analytical calculation of temperature field in anisotropic capillary structures using a pseudoconvection model have been considered. Calculation results have been compared with experimental data.