Study On3-D Numerical Simulation Of Turbulent Flow And Measurements Of PIV In The Flow Field Of Centrifugal Pump

Due to the long and short blades can avoid jam in the inlet of the impeller for too many vanes, prevent vortex and flow separation from generating and developing, improve the diffusion of impeller passage, centrifugal pump with long and short blades has the excellent performance, such as little discharge, high water-head, high efficiency, wide and stable operating range etc.. Moreover, the structure of the pump is compact, and its maintenance is easily. So the centrifugal pump with the long and short blades is successfully and widely applied in petrochemical, light industry and aerospace engineering.The different schemes of short blade setting have different effects on centrifugal pump performance, so it is necessary to study the influence of internal characteristic to external characteristics. The three-dimensional turbulent numerical simulation is adopted to study internal flow pattern of theree pairs of centrifugal pumps with splitting blades, and the particle image velocimetry (PIV) is adopted to study the internal flow pattern of two impellers. The distribution rule of flow parameters in the centrifugal impeller is analyzed. In the end of the paper, three pairs of low-specific and high-speed pumps are designed on the basis of previous studies and ANSYS CFX software is used to simulate the three-dimensional steady turbulent flow in the low-specific and high-speed pumps. The result of the study is important reference to further optimization design.The contents mentioned in this paper are as following:1. Both of the AutoCAD and Pro/ENGINEER software are used to model impellers and volute, and the mesh of the impellers and volute is meshed with structured grid by ICEM-CFD.2. Based on the time-averaged N-S equation set and the standard κ-ε turbulent model, the steady numerical simulation of the three-dimensional turbulent flow in the flow-passage of the centrifugal impellers with long and short blades are simulated on the platform of commercial software (ANSYS CFX11.0). The steady numerical simulation is used in seven conditions of three pairs of centrifugal pump impellers. The distributions of static pressure and relative velocity in the interior flow of the impellers are captured, and these flow parameters are analyzed comparatively. 3. Using the particle image velocimetry(PIV)measurement technology, the internal flow fields in the same passage of two pairs of centrifugal impellers are investigated at five flow patterns. Relative velocity vector and isoline of symmetrical section are obtained. The distributions of relative velocity are analyzed comparatively.4. The results of numerical simulation and PIV are analyzed comparatively. The paper analyzes the reasons of the difference between numerical simulation and PIV measurement’s result.5. The design method of low-specific and high-speed pump is introduced, three pairs of complex impellers with different starting diameter and volute are designed. The mesh of the high-speed pump is meshed with unstructured grid by ICEM-CFD. The three-dimensional numerical simulation is carried out in five flow conditions. The static pressure and relative velocity distributions of them are analyzed comparatively. The influence of difference starting diameter on the internal flow of impeller is also analyzed.