Study On Operating Performance Of Axial-Flow Pumps

Axial-flow pumps are widely used in different field, such as irrigation, city water supply and drainage, water transfer project and so on. The operating performance of axial-flow pump has substantial influence on the cost, operation and maintenance of a pumping station. It is very important to research the operating performance of axial-flow pumps.This paper is focused on the study of inner flow field and performance prediction of axial-flow pumps through the method of numerical simulation. A integrity CFD analysis model is established. Unstructured grid is adopted and the gird near blades are meshed fine. Based on the 3D time average Navier-Stokes equations and the standard k - ε model, RNG k -ε model and Realizable k - ε model, the 3D turbulent flow field of an axial-flow pump is computed. Reasonable distributing of velocity and pressure in the impeller are obtained. According to calculated results of the flow field, the predicted performance consistent well with the experiment data on the conditions near the design condition, but it appears unsuitable for computing other operating conditions especially on part-load conditions. For confirming the relation between the performance and the rotate speed, the simulations of an axial-flow pump at different rotate speeds have been finished. The changing of inner flow field following with rotate speed, especially the pressure distribution of blade suction side are discussed and analyzed. The values of NPSHr at different rotating speeds are obtained. Finally, the simulation of entire pump flow-passage with suction elbow is performed. The results could be used to direct the design of passage parts of axial-flow pumps.