Abstract: In order to study the 3D turbulent flow in pump, the multiple reference frame was set between impeller and volute casing to compute the coupling question of FY underwater pump based on the Reynolds-averaging equations and the standard two equations turbulent model. From the computed information of flow field, the velocity and static pressure distributions in underwater pump were obtained. The computation results indicate the following results: Relative velocity increases first and then decreases along pressure side of blade, and the opposite rule occurs along suction side; The velocity and pressure distributions are dissymmetry in impeller; The pressure gradient changes highly near the volute tongue; The velocity is dissymmetry at the segment of volute outlet and fluid in volute casing flows as the type of vertex. The results of the numerical computation could be referred for further researches.

Key words: Impeller, Numerical computation, Turbulent flow, Underwater pump, Volute casing