Pump Optimization

Sheet light flow visualization was used to understand and optimize the flow in a small centrifugal pump.

A pump was exhibiting low efficiency. Excess turbulence and unsteady flow were suspected as contributing factors. Flow visualization showed areas of recirculating, turbulent flow.

^ The above photo shows an area of recirculation near the inlet of the pump. The flow is from top to bottom. This is caused by too great of an expansion angle in the pump inlet. A mpg movie ( 1.6 MB) is available by clicking on the image.

^ The outlet of the pump in cross section, The dark object on the right is the pump impeller. In this case the pump outlet is too large, and this causes a double vortex in the pump outlet. Another issue with this pump is that the spacing between the top of the impeller and the housing is too large, allowing the high pressure outlet flow to go back to the inlet. Click on the image for an mpg video. The video ( 4.9 MB) shows the flow pattern as the sheet light is scanned backward and forward.