Numerical Analysis Of The Centrifugal Pumps' Cavitation And Wear Influenced By Sandy Water

Centrifugal pumps have played a crucial role in the transportation of water,irrigation,flood control,drainage projects,and the national economy.At the same time,our country's rivers are mostly silt,centrifugal pumps will contain sediment and solid impurities at different levels in the process of transporting the water,and these solid particles will inevitably cause certain wear and cavitation damage to the flow-through components during operation of the centrifugal pumps.In the study of the mechanism of the rapid destruction of flow-through components of centrifugal pumps by sand-bearing water flow,domestic and foreign scholars proposed three viewpoints:(1)the cavitation of centrifugal pump damages the flow-through components(2)destruction of centrifugal pump caused by sand wear,(3)both work together to destroy the centrifugal pump.Therefore,when the sandy water is used as the medium,the research on the internal flow characteristics,cavitation position,and wear patterns of centrifugal pumps is very significant to ensure its safety,stability,and high efficiency.This article aims at the design of centrifugal pump numerical simulation in clear water and sandy water conditions.The main work and conclusions of this article are listed as follows:Firstly,according to the three-dimensional structure diagram and basic design parameters of the centrifugal pump,by using the specialized pump mechanical design software CFturbo,the centrifugal pump's flow-through components are three-dimensional modeled,and the threedimensional model of the centrifugal pump is optimized through the modeling software UG10.0.Then the ICEM software is used for meshing,and CFX software to calculate the constant value of the full flow channel of the centrifugal pump under clean water conditions.The results show that the internal flow characteristics of the centrifugal pump under clear water medium conditions meet the theoretical design requirements of the centrifugal pump,so the designed centrifugal pump can be used for subsequent numerical simulation.Considering that the pressure at the inlet of the centrifugal pump is low and the cavitation is easy to occur,and based on two tandem centrifugal pumps with the same model and size,which have the same flow velocity and basic geometric parameters,this paper only changed the pressure of centrifugal pump,the main reasons for the destruction of the flow-through components of the centrifugal pump caused by sediment abrasion and cavitation are compared and analyzed when the serial centrifugal pump transports the sand flow in different working conditions.When the pump conveys the sand-containing medium,it can suppress the cavitation at the inlet of the centrifugal pump impeller by increasing the pressure of the sand-containing water into the inlet of the impeller;however,by changing the operating conditions such as the sand particle size and the sand weight,etc.only the wear strength of the flow-through components such as the suction surface of the centrifugal pump blade suction surface and the pressure surface outlet surface can be strengthened,and the position and degree of damage of the cavitation erosion of the centrifugal pump remains unchanged.