LAUSR

Abstract The 3D printed wicks, whose structural parameters could be controlled by changing the distance between neighboring structural cylinders, were manufactured to experimentally investigate the effect of pore size (d) on the heat performance of the loop heat pipe (LHP). With the help of the 3D printing technique, the order 3D printed wicks with all pores interconnected were fabricated to avoid high randomness and appearance of closed pores in the traditional sintered wicks. In addition, high porosity, suitable pore radius, low effective thermal conductivity and high permeability were also realized in the same wick. A flat LHP with a transparent evaporator and vapor line was fabricated to observe the flow motion in the evaporator and the vapor line. It was indicated that the LHP with a 3D printed wick (d = 200 μm) made of stainless steel could start successfully in about 100 s at a low heat load of 20 W (2.83 W/cm2). And a stable operation in a wide heat load range from 20 W to 160 W (22.63 W/cm2) was achieved with the allowable evaporator wall temperature of 100 oC. The minimum evaporator thermal resistance of the 3D printed wick was 0.031 K/W at a heat load of 140 W with a corresponding maximum heat transfer coefficient of 44,379 W/m2K. The minimum LHP thermal resistance was 0.181 K/W at a heat load of 160 W.