Exploring the effect of v-shaped cut at blade exit of a double volute centrifugal pump

The effect of V-cut at impeller blades' exit on internal pressure fluctuations, case vibration, and performance of a double volute boiler-feed pump has been investigated. Scaled model pump and two impellers, with and without the V-cut, were used in a closed water test loop to conduct experimental testing. The V-cut increases the effective gap between the trailing edge of the impeller blades and volute tongue reducing the impeller-volute interaction, which is the origin of pressure pulsation inside the pump. It reduces pump vibration by different amounts depending on flow rate. The V-cut is more effective in reducing pressure fluctuations at off-design conditions. The reduction in pressure fluctuations and pump vibration was achieved at the expense of pump head. The energy content of pressure fluctuations measured at discharge and suction pipes proved to be insignificant compared to those measured inside the pump.