An innovative Device to Suppress Performance-Curve instability in a Mixed Flow Pump by Use of J-Groove

摘要

In order to control and suppress a performance-curve instability characterized by a local dent in head-capacity curve or an uprising head-capacity curve in a mixed flow pump, an innovative and very simple device of using shallow grooves mounted on a casing wall is proposed. The optimum dimension of the groove and its location for the instability suppression are determined experimen- tally. The results show that the shallow grooves located with proper dimension can sufficiently suppress the instability for all discharge ranges. The remarkable effect of shallow grooves is to decrease both the swirl strength and the size of the reverse flow region at an impeller inlet by use of angular momentum absorption through the mixing between the main flow and the groove flow, resulting in the recovery of impeller theoretical head.