Analysis Of Pressure Pulsation Of Pump Turbine Based On CFD

With the rapid development of China’s economy in recent decades and the proposal of 2060 carbon neutrality target,the hydropower accounts for an increasing proportion of the total power generation,and the pumped storage power station is an important development object.The pressure pulsation is an important factor affecting the stable operation of pump turbine.To solve this problem,this thesis usescomputational fluid dynamics(CFD)to carry out the full flow channel numerical analysis,and explores the influence of different conditions and non-synchronous guide vane on the internal flow of pump turbine,and compares and analyzes the relationship between the flow field in the different conditions and pressure pulsation.The main research contents are as follows:Using three-dimensional modeling software Solidworks and Unigraphics NX to perform 3D solid modeling of the flow passage of the water pump turbine.The spiral case,fixed guide vane,movable guide vane and tailpipe are structured meshed by ICEM meshing software,and the runner wheel is structured meshed by Turbogrid,professional rotating machinery meshing software.The SST-turbulence model is used to numerically calculate the overall internal flow of the pump-turbine,and the pump-turbine with a guide vane opening of22.5mm is simulated under different flow conditions.The results show that the pressure in the bladeless zone of hydraulic turbine operating conditions and pump operating conditions present periodic distributions on the temporal and spatial scales.The main factor of the pressure distribution in the bladeless zone of hydraulic turbine operating conditions is the movable guide vane and the secondary factor is the runner blade.The pump operating condition The main factor of pressure distribution is the runner blade,and the secondary factor is the movable guide vane.The pressure pulsation of the pump condition is stronger than that in the turbine condition.The influence of two or four non-synchronous guide vanes with different openings on the internal flow characteristics and pressure pulsation of pump turbine is studied under the condition of low flow rate.In the case of guide blade opening of 15mm:(1)the pre-opening of No.7 and No.17 guide vanes is 19mm;(2)the pre-opening of No.7and No.17 guide vane is 23mm;(3)the pre-opening of No.7 and No.17 guide vanes is27 mm,(4)the pre-opening of No.6,No.7,No.16 and No.17 guide vanes is 19mm;(5)the pre-opening of No.6,No.7,No.16 and No.17 guide vanes is 23 mm.The internal flow and pressure pulsation of pump turbines in different schemes are compared and analyzed when the speed of the runner increases.The simulation results can be used for reference to reduce pressure pulsation by using non-synchronous guide vane in turbine boot condition.