Development Of Hydraulic Model And Performance Research Of Vertical Mixed-flow Pump

The mixed flow pump has the characteristics of large flow and high head.It is widely used in water treatment,water conservancy engineering and water circulation system of power station.Mixed flow pump is between centrifugal pump and axial flow pump in terms of hydraulic characteristics,which can meet the needs of a wider range of users.However,in practical engineering applications,the requirements of mixed flow pump are increasingly high,which not only requires high hydraulic efficiency,but also requires high cavitation and working stability.In this paper,based on the needs of actual engineering topics,the hydraulic model of large-scale vertical mixed flow pumps is developed,and the numerical simulation of the full flow channel under clean water conditions and sand water conditions is carried out.At the same time,the operation status of the mixed flow pump and the pressure fluctuation of each flow passage part are compared and analyzed when it is running in different fluid medium.The main research results of this paper are as follows:1.Analyzed the current research situation of mixed flow pumps at home and abroad.Based on the similarity conversion algorithm,the hydraulic design of the impeller part of the vertical mixed flow pump was carried out.The calculation method of radial guide vane is discussed,the guide vane model is optimized,and the development of the full channel hydraulic model of vertical mixed flow pump is finally completed.2.Using UG to draw the three-dimensional model of the whole flow passage of the mixed flow pump,and using zebra pattern to check and evaluate the surface smoothness of the impeller blade.Selecting ANSYS ICEM to mesh different parts of vertical mixed flow pump,After grid independence verification,based on ANSYS-CFX,the steady numerical simulation of the whole flow passage of vertical mixed flow pump is carried out,the change of hydraulic performance of vertical mixed flow pump under five different flow conditions including design flow conditions is obtained,and the distribution of internal flow field of each flow passage part is studied.3.Pressure pulsation plays an important role in the research of pump.It can induce the vibration and noise in the process of pump operation.Based on the results of steady calculation,this paper studies the unsteady state,sets monitoring points in each flow passage part of vertical mixed flow pump,and explores the pressure fluctuation situation of different flow passage parts when the vertical mixed flow pump is running in the clear water medium,which provides an important reference for the next optimization.4.Based on the consideration of engineering practice,this paper analyzes the distribution of solid particles on the surface of each component of the vertical mixed flow pump operating in the sediment laden water medium in different flow conditions,And studys the wear characteristics of each part of the vertical mixed flow pump based on the distribution of sediment,at the same time,compares and analyzes the pressure fluctuation of vertical mixed flow pump in clear water and the sediment laden water medium.Through simulation analysis,it can be seen that the hydraulic performance of each overflow component of the developed vertical mixed flow pump hydraulic model is good,which can meet the design requirements well and operate stably.