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 ℃, and the thermal resistance is 0.01 ~ 0.07 K/W. The maximum heat-transport capacity of HP sample A is 66.3 ~ 88.4 W•m at different condensation temperatures, which is 4.0% ~ 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 ~ 0.997 K, and the working condition and performance are excellent.