Abstract
In the present study, the head/discharge characteristics of a centrifugal pump depending on the direction of partial load operation have been investigated through calculating internal flow. Based on the hypothesis of axisymmetric flow, the numerical simulation on the incompressible turbulent flow has been carried out for partial blade-passages with periodic boundary conditions. In the numerical calculation, the data previously calculated at a little more or less discharge are given as the initial condition. In the numerical results at partial flow operations the pump has the large backflow and recirculation regions in three locations, one of which is near the casing at the impeller inlet, another of which around the fins and the other of which near the central part of the diffuser. The scale of these regions varies steeply under two partial flow operation points as the discharge increases or decreases. As a result, the hysteresis loop appears in the head/discharge characteristics curve depending on the direction of partial load operation.
