Abstract:Based on the finite volume method, the 3D steady turbulent flow in a centrifugal pump was simulated under different conditions using the standard turbulence model, the velocity distribution of the recirculation flow field and vortex morphology were analyzed.The flow field in the suction pipe was visualized using a Ploymethyl Methacrylate suction pipe, and the injected air bubbles were used as tracers.The flow patterns under different conditions were shot with a high speed camera.The results indicated that the capacity of the recirculation onset is 0.7 Qd.As the flow rate decreases,the recirculation intensity and its axial velocity at the entrance to the impeller and in the suction pipe are increased. Meanwhile, the recirculation vortex becomes so big that it partially blocks the flow passages.A strong prerotation is created; it can travel upstream along the suction pipe for a long distance even up to 10 times the impeller inlet diameter.At the shutoff condition, a rope vortex appears in the suction pipe.
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