Hydraulic Performance Comparison of Centrifugal Closed Impellers Fabricated by Means of Additive Manufacturing and Classical Machining for Space Active Thermal Control Systems of Satellites

The current paper addresses the challenges in manufacturing a critical component of a centrifugal pump for space active thermal control systems of satellites, namely, the closed centrifugal impeller. Compared to the classical technologies, there is an obvious advantage of additive manufacturing of closed impellers, due to the possibility of creating complex geometries, which boost the hydraulic performances of the part and, implicitly, of the pump. In this regard, the authors performed a comparative analysis between a closed impeller obtained by classical machining and three manufactured by additive technology (selective laser melting) by means of dimensional inspection, non-destructive testing, and experimental evaluation. The study performed here showed that the additively manufactured closed impellers exhibited similar hydraulic performances to the classical one, without the need for performing post-processing of internal surfaces. Also, in terms of dimensional and geometrical stability, the additively manufactured closed impellers were within the imposed tolerances, demonstrating the feasibility of obtaining such complex parts by using additive manufacturing. Subsequently, the allocated time for manufacturing decreased by 75% for the closed impellers manufactured by additive technologies, and the need for using four technological processes was decreased to only two, printing and post-processing.