Numerical Simulation Of Interior Flow For High Specific Speed Mixed-flow Pump And Its Characteristics Prediction

Along with the development of national economy and the great demand of energy and environment, there is an urgent requirement for the improving of pumps performance. By reasonable design of impeller, stator and volute, the distribution of pressure and velocity in flow passage can be changed, and the pumps performance can be improved correspondingly.This paper coupled the intake, the impeller, the stator, and the siphon together, calculated the 3-D interior turbulent flow field of the mixed-flow pump under different flow rate and vane angle. The main flow characteristics were obtained by analyzing the distributions of velocity and pressure, and the physical message of the capability and improvement were presented for the pump.The main work of this paper consists of:1. A brief description of the mixed-flow pump development and objective analyses were given. The characteristics of this style pump were summarized, and the 211-80 type model was introduced, which was developed by the Research Center of Fluid Machinery and Engineering of Jiangsu University. The governing equations, dispersible solutions and different grid generated techniques in the calculated flow field were discussed.2. The Pro/Engineer software was applied to design the whole pump. The hydraulics professional software Gambit was used to carry on generating mixed and unstructured grids of the whole calculated region. Two-equation mode and the wall function were adopted to enclose the N-S equation and to avoid the laminar sub layer, accelerating the solution. The turbulent flow mode based on Reynolds time-averaged governing equations andκ-εtwo-equation turbulent mode was adopted. The SIMPLEC algorithm was used to solve the N-S equation. The numerical simulation of the 3-D interior incompressible turbulent flow field in the mixed-flow pump was carried out according to different operation points.3. By analyzing the inner flow for high specific speed mixed-flow pump, the distributions of velocity, pressure and turbulence kinetic energy in the flow field are obtained. Some results were concluded that the minimum and maximum values of static pressure in the vanes' pressure side are descending gradually with the flow rate increasing. The distribution and transformation of velocity in pressure side accord with general rules in the impeller of mixed-flow pump. The secondary circumfluence phenomenon is caught in the position of stator inlet, and the preventive method is given.4. The characteristics prediction method and expressions were introduced. The performance curves of this style pump were drawn by calculating the values of H, P, andηin every working point. By comparing with the experiments, it shows that the result of numerical simulation is consistent with the experiments and the characteristics prediction can reflect the transformational rules of the performance parameters. The error increases as the increasing of turbulence intensity.