Effect of Geometry on the Performance of Miniature Heat Pipe

Abstract

An experimental study is performed to investigate the effect of geometry on the performance of miniature heat pipe (MHP). The experiment is conducted with circular and square MHPs having the same hydraulic diameter of 5 mm and length of 150 mm with acetone as the working fluid. The major findings in the investigation are as follows. At a constant heat flux, coolant flow rate and inclination angle, wall temperatures of evaporator section of circular MHP are higher than that of the square MHP. With the decrease in both inclination angle and coolant flow rate, the rate of increase in wall temperature of the evaporator section for circular MHP is higher than that of square MHP. Thermal resistance of the circular MHP is almost independent of coolant flow rate but for square MHP, thermal resistance decreases with the increase in coolant flow rate. Again at a constant coolant flow rate, heat flux and inclination angle, the thermal resistance for square MHP shows much smaller value than that of circular MHP. Overall heat transfer coefficient for square MHP is maximed at vertical orientation.