Low Specific Speed Centrifugal Composite Impeller Internal Flow Values ​​calculated

Centrifugal pump at low specific speed is widely, used in many fields of the modern industry. However, its defects of lower efficiency and working instability under the operating condition of small flow rate limit its application in agriculture and industry. Compound impeller is put into application of centrifugal pump at low specific speed in recent years and good. results have been gotten. But the study of inner flow for compound impeller is not involved yet. The destination of this paper is that investigating how the efficiency of the centrifugal pump is affected while the compound impeller is used in it through the numerical study for its inner flow. The significance of the study lies in two aspects, in the one hand, the appropriate numerical calculating method for the inner flow of compound impeller in the centrifugal pump at low, specific speed is obtained; in the other hand, the attempts of supplying the gap of the study in this field are made. Based on a great number of experiments of numerical calculation, following conclusion should be made: (1) Singularity distribution method is applicable in the inner flow study of compound impeller in the centrifugal pump at low specific speed. (2) The laws of the effects of the related parameter election on the calculation results are obtained. (3) The characteristics of the inner performance of?the compound impeller in the centrifugal pump at low specific speed are obtained from the study of the inner flow.