Thickness Influence of the Copper Powder Sintered Capillary Structure in the Thermal Performance of Heat Pipes

Abstract

A selection of capillary structure of sintered copper powder for heat pipes based on the experimental thermal performance was conducted. Due to the geometric characteristics, the manufactured heat pipes can be used in electronics cooling. The heat pipes are used to enhance the heat transfer and are based on phase change. The sintered metal powder structures have a high capillary pumping, low pores, and good thermal conductivity. The heat pipes were manufactured from a straight copper pipe with an external diameter of 9.45mm, an inner diameter of 7.75mm, and a length of 200mm. The capillary structure was made of sintered copper powder with three different thicknesses (2.125mm, 1.500mm, and 0.875mm). Distilled water was used as the working fluid. Each thickness was analyzed with four different filling ratios related to the evaporator volume: 60, 80, 100, and 120%. The condenser was cooled by forced convection of air, the adiabatic section was insulated, and the evaporator was heated by an electrical resistor and was insulated from the environment with aeronautic insulation. The heat pipes were tested horizontally under different low heat loads (from 5 up to 45W). The experimental results showed that all sintered heat pipes worked satisfactorily. However, Type #3 Heat Pipe with a filling ratio of 100% showed the best thermal performance.