Abstract：The RNG k-ε turbulence model was used to simulate the turbulent flow in the centrifugalimpeller with or without shroud. It is found from the calculation results of the shrouded impeller that there is alarge area of recirculation flow near blade suction surface at low flow rate, and there is an obvious vortex justupstream of the impeller leading edge near shroud at high flow rate. The existences of clearance in theunshrouded impeller arouse two vortices. Compared with shrouded impeller, the head, capacity and efficiencyof the unshrouded impeller decrease. The best efficiency is lowered by 18%. A transparent acrylic centrifugalpump which is suitable for PIV measurement has been developed. The results of PIV measurement can be usedto validate the numerical solution and show that the flow in one passage is different to another even at bestefficiency point.
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