Heat Transport Capability of Axial Grooved Heat Pipes. Capillary pumping limit under micro- and normal-gravity condition with asymmetrical heating.

Abstract

Heat pipes have capillary pumping limit when they operate under micro-gravity condition or axially top heating mode under normal-gravity. A theoretical model was developed to predict temperature rise in evaporator with asymmetrical heating and the capillary pumping limit. In this model, puddling effect, liquid recession into groove bottom and 3-dimensional heat conduction in the evaporator were taken into consideration. The prediction under micro-and normal-gravity condition agreed well with experimental data. It is found by calculation that the temperature at the evaporator end begin to increase just after all gooves dry out at the evaporator end in case of both symmetrical and asymmetrical heating and the capillary pumping limit is not much affected by heating condition when the thermal conductivity of heat pipe envelope is large.