Performance analysis and experimental verification of hydraulic driven axial flow pumps

To investigate axial flow pumps’ performance characteristics, NUMECA software is selected to perform numerical simulation at four rotating speeds (1380, 1840, 2300, and 2530 r/min) based on the Spalart-Allmaras turbulence model. The relationship curves of flow-head and flow-pump efficiency, static pressure distribution on blade surfaces, velocity variation near the hub, and total pressure distribution at different blade heights are obtained. Results indicate that with the improvement of the rotating speed, the curves of the head and the efficiency rise and shift to the right, the pressure difference on both sides of the blade ascends, and the moment acting on the blade induced by the water flow also increases, resulting in higher head. At the rated speed of 2300 r/min, the pressure difference between the pressure side and the suction side at low flowrates increases, the minimum pressure is lower, and the anticavitation performance decreases, whereas the velocity distribution near the hub is the same at different flowrates. Moreover, the velocity is lower near the hub’s leading edge, and no influence is observed. To guarantee the reliability and comparability, experimental data are contrasted with the simulated results at the speed of 2182 r/min. At the near design condition (Q = 534.4–567 m 3 /h), the relative deviation of efficiency and head is less than 4.5 %, which is a small gap. These conclusions provide valuable reference for axial flow pumps to operate under variable speed conditions.