Thermal performance of a thin flat heat pipe with grooved porous structure

The heat transfer performance of a composite porous heat pipe (CPHP, 95 mm × 60 mm × 2.5 mm) using a grooved porous structure as capillary wick was studied. Sintered copper powder was used as the main structure of the capillary wick and sintered as grooves. A new type of powder filling method was used to make a capillary wick and can reduce the use of graphite molds. The effects of heating power, wick width (included 20, 25, 30, 35 mm) and copper powder particle size (included 75–96, 96–120, 120–180 μm) on the thermal performance of CPHPs has been studied experimentally. The results showed that the designed flat heat pipe had a fast thermal response speed, and the heat pipe temperature began to stabilize at 250 s. For different wick width heat pipes, the optimized wick width can improve the CPHP's thermal performance due to the high vapor-liquid circulation efficiency, and its limiting power and minimum thermal resistance were 85 W and 0.067 °C/W, respectively. Moreover, according to the results, small particles have greater capillary pressure and lower permeability. When the copper powder particle size decreased, the thermal resistance and limiting power of CPHPs decreased. The limiting power of different structural heat pipes could reach 85 W, and the maximum effective thermal conductivity could reach 8000 W/(m·°C).