Study on the influence of inducer blade number on cavitation characteristics of aerospace liquid cooling pump

Abstract

To investigate the influence of inducer blade number on the cavitation characteristics of an aerospace liquid cooling pump under high rotational speed and low inlet-pressure conditions, three pump models equipped with 3-, 4-, and 5-blade inducers were established. Numerical simulations were conducted using the RNG k–ε turbulence model and the Zwart–Gerber–Belamri cavitation model. The hydraulic performance, pressure distribution, and cavitation evolution under different flow rates and inlet pressures were analyzed. The results show that the inducer blade number has a limited influence on the overall pump performance near the design condition. However, under high-flow-rate conditions, increasing the blade number reduces the effective flow passage area, intensifies local flow acceleration and hydraulic losses, and leads to a greater head reduction. The cavitation results indicate that the effect of inducer blade number is stage-dependent. At relatively high inlet pressures, the 5-blade inducer provides stronger flow guidance and results in a lower vapor volume fraction, showing better suppression of cavitation inception. As the inlet pressure decreases further, the narrower passages of the 5-blade configuration enhance local acceleration and low-pressure-region expansion, causing rapid vapor growth and earlier performance deterioration. Based on the 3% head-drop criterion, the critical inlet pressures of the 5-, 4-, and 3-blade models are approximately 17,000 Pa, 16,000 Pa, and 13,000 Pa, respectively. The results suggest that the influence of inducer blade number on cavitation performance is governed by the competition between flow uniformization and passage constriction. It should be noted that the present study is based on numerical simulations, and the predicted cavitation behavior, critical inlet pressure, and proposed mechanism require further experimental validation.