Abstract
To clarify the effect of inlet flow condition on the performance of the mixed-flowpump at partial flow rate, experiments were executed under the condition of different gaps between the bell mouth and the bottom wall, and with the baffle for interrupting the recirculating flow in front of the bell mouth. Velocity and pressure distributions were measured at inlet and outlet of the impeller. Results showed that inlet reverse flow was formed less than about 60% of design flow rate and developed large scale recirculating flow less than about 40% flow rate. Pump head and shaft power near shut off condition were mainly determined by the flow pattern inside and outside of the bell mouth.
