Experimental and numerical flow field analysis of a mixed flow pump impeller

摘要

Mixed flow centrifugal pumps of certain specific speeds exhibit unstable pump performance at partial flows that could lead to users system instability. To study the root cause of this behavior, detailed experimental and numerical studies were conducted on a typical mixed flow impeller. The experimental work was conducted on a nominal 20 inch size mixed flow pump of specific speed 6500 (in gpm, ft, rpm). In addition to the pump head, flow, power measurements, and detailed flow field data were taken by using a three-hole Cobra probe and dynamic transducers. The numerical study was conducted by using a commercially available CFD code. A three-dimensional computational grid of the impeller vane passageway was built, and numerical solutions were derived at the several flows at which the experimental data were obtained. In addition to the pressure and flow velocity angles, details of the flow field were observed at pertinent locations of the impeller.