Heat transfer enhancement in two-phase systems with capillary pumps

Heat transfer in capillary pumped loops (CPL) is carried out by transferring the mass of the circulating coolant in the form of liquid and vapor. Therefore, the hydrodynamics of the phases in the CPL determines their heat transfer capacity (heat flow or the product of the heat flow by the heat transfer length). The influence of structural, hydraulic and thermo-physical properties of capillary structures used as capillary pumps in two-phase thermal control systems (Loop Heat Pipes – LHP) on their heat transfer capacity has been analyzed. Methods of increasing the heat transfer capacity of LHP, due to the use of anisotropic capillary structures with a decrease in pore sizes in the direction of the vaporization zone, have been determined. The conditions of LHP operability and the method of analytical calculation of the temperature field in anisotropic capillary structures for a model with pseudo-convection have been considered. The calculated and experimental data have been compared.