Influence of Guide Vane Geometry Parameters on Pressure Pulsations in Hydraulic Turbines

In order to improve the operation stability of the guide vane hydraulic turbine, this paper studies the influence of geometric parameters of guide vanes on pressure pulsation of hydraulic turbine, and radial guide vanes are added before the IS80-50-315 low specific speed centrifugal pump reverses to make the inlet of hydraulic turbine impeller. For the outlet angle of guide vanes, the number of blades and the radial height, orthogonal experimental design is adopted to match the same impeller shape to form a new hydraulic turbine model. CFX software is used to the clearance between the guide vane and the impeller and the monitoring points set along the circumference of the impeller are used for steady and unsteady numerical calculation. The range analysis of the steady calculation results of the orthogonal test design is carried out, and the main and secondary factors affecting the hydraulic turbine performance caused by the geometric parameters of the guide vane are analyzed. Finally, the optimal scheme combination is obtained. Then, the time domain and frequency domain analysis of the unsteady numerical calculation pressure pulsation results are carried out. The results show that the influence of the geometric parameters combination of radial guide vanes on hydraulic efficiency and water head is that the number of vanes is greater than the radial height and the outlet angle. The pressure coefficient of the guide vane hydraulic turbine is the largest in the clearance between the guide vane and the impeller, and the smallest in the impeller; When the number of impeller blades is the same, the value of radial guide vane outlet angle and radial height is selected to be smaller within a reasonable range, which is conducive to reducing the amplitude of pressure pulsation of the guide vane hydraulic turbine and improving the stability of operation.