Cavitation suppression and energy performance improvement for a mixed flow pump through controllable velocity moment

In this paper, a multi-objective optimization strategy for a volute mixed flow pump is implemented based on inverse design theory. The controllable velocity moment (CVM) design parameters are defined based on the impeller outlet velocity moment and its partial derivative in the streamline direction, and flow control is further realized by directly adjusting the velocity moment distribution inside the impeller. The significance order of the effect of the CVM parameters on the efficiency and NPHS_c at the best operation points is first investigated, and the elliptical basis function (EBF) approximation model and MOPS optimization algorithm are combined to carry out multi-objective optimization. Compared with the baseline model, an improvement in the efficiency and head at the best operation points of 0.48%, 1.07 m is obtained for the optimal model, with a widened and efficient operation range, and NPHS_c is reduced from 4.545 m–4.235 m, with a slowed cavitation development. The proposed CVM method effectively realizes flow control under multiple conditions, optimizing the pressure distribution on the blade pressure side and suppressing the reverse jet in the cavity closure area.