Computation of unsteady flow and performance prediction for centrifugal pump

The unsteady flow in a centrifugal pump was computed by applying Reynolds-averaged equations closed by SST k-ω model and slide-mesh-method. Taking leakage loss, disk friction loss and mechanical loss into account, the performance curves of pump were predicted based on the computation results of unsteady flow, and were compared with the experimental data. The results show that the head and shaft power fluctuate greatly with different relative position of impeller blade and diffuser volute for a given flow rate, and the fluctuation amplitudes increase with flow rate increasing. The performance curves predicted of the steady and unsteady flow computation have little difference at both large flow rate and design point, but have obvious difference at low flow rate. Compared with tested curves, the predicted head and shaft power curves are lower, and the predicted efficiency curve is similar. Because of little difference between steady and unsteady flow computation at design point, the results of steady flow computation is feasible for impeller design.