Analysis Of Internal Flow Field And Performance Predictions Of Hydraulic Turbine Based On Centrifugal Pump

It can recover the liquid pressure energy to drive pumps,fans,generators and other rotating machinery using pumps in reverse operation.Some studies show that it is essential in selecting the proper pump and working instability by a large numbeir of researchers.Many results on the former at home and abroad,but they are mixed,and some even be significantly different with experimental data;unstability is the phenomenon that the efficiency curve downward sharply in the small flow condition,which research is relatively few on,that motors are needed to work with reversal pumps in practice.So,the investigation for above two issues are done in this paper from the following aspects based on the results of the previouis studies.(1)Combined with the previous method predicting the parameters of optimal condition for pump inversion,this paper gives a more comrehensive and broader applicability of the mathematical model predicted relationship.Statistical way used to analyze the test result of numerical simulation for three chemical centrifugal pumps,a new equations are presented to estimate the performances of optimal condition in reverse mode.(2) The three typical operating conditions (big flow condition,the optimal working condition and small flow condition)are selected to test for a centrifugal pump in order to analyse the performance of the axternal features in reverse conditions from the distribution of pressure and velosity of internal flow fields.(3) According to the pareameters of reverse centrifugal pump in the most optimum conditions and the design method of conventional guide vane for mixed-flow turbine design a guide vane for the centrifugal pump. And compara ansysize the experiments results of centrifugal pump with guide vane and pump without guide vaneThrough the research on the above issues, concluded that:(1) The predicted equation of performance parameters in the most optimum conditions of pump reversal. The results of the calculator is almost the same with the experiental results,and it can be applied in the engineering practice. The equation is only valid for low specific speed centrifugal pump with single-stage and single-suction recommended by this article.(2) Through the numerical simulation and analysis of internal flow field in different work conditions can draw the conclusion that:even in the most optimum conditions,there is a vortex in the relative velosity of leading face of vane and the flow disorders in the edge of inlet. The reason for it is that the most optimum conditions of reverse is bigger than forward,negative angle in the wheel is a little big,and the flow attack the blade.(3) The guide designed indeed improve the inflow conditions of runner,and the relative velocity vector distribution is good in the leading face and back face of blades.Compare to the situation without guide vanes,the optimum condition shifts forward a large flow.Although the value of the highest efficiency is lower,the stability is enhanced.