Experimental Investigation of the Performance of a 3D Printed Heat Pipe with Ultra-Small Bending Radius for Space Applications

Highly integrated aerospace products have a small interior space; thus, heat pipes (HPs) with a small bending radius are required for thermal management. An HP sample with an ultra-small bending radius and a capillary channel is fabricated by 3D printing. The cross-sectional area of the sample and its heat transfer capacity are compared with that of a standard aluminum-ammonia channel heat pipe (ACHP). The L-shaped HP samples consist of three sections: two straight parts (L1 and L2) and a curved part with a bending radius of R. A prototype is designed and manufactured for an on-orbit flight test. Statistical methods are used to calculate the filling volume of the working fluid. The maximum heat flow of the HP sample A is 140.0 W at a cold plate temperature of 10.0 degrees C, and the thermal resistance is 0.01 similar to 0.07 K/W. The maximum heat-transport capacity of HP sample A is 66.3 similar to 88.4 W.m at different condensation temperatures, which is 4.0% similar to 18.4% lower than that of HP samples B and C. The on-orbit flight data show that the temperature difference between the two ends of the 3D printed HP is 0.001 similar to 0.997 K, and the working condition and performance are excellent.