Novel sealing design for high-speed coolant pumps: Impact on energy performance, axial thrust and flow field

High-speed coolant pumps are critical devices for driving fluid circulation in the thermal management systems of various vehicles. However, the current pump sealing design is plagued by high energy losses and axial forces. Four sealing schemes were developed for the pump's front chamber. Case A uses an annular seal, Case B employs a labyrinth seal, Case C combines both, and Case D introduces a new labyrinth seal at the impeller entry. Numerical simulations were conducted, and the simulation results showed good agreement with the experimental data. The seals have a smaller impact on the head but significantly affect the efficiency, with Case D being 2.4 % more efficient. Besides, different seals generate varying front cavity pressure distributions and axial thrusts, with the axial force in Case D being the smallest, reduced by 25 %. Interference of backflow with the main flow at the impeller inlet differs across seal designs, with Case D minimizing interference and flow losses. Compared to the other seals, Case D significantly reduces the high-entropy production area at the impeller inlet. By analyzing energy performance, axial thrust, and flow field, Case D is identified as the optimal design, offering insights for improving vehicle thermal management systems.