Numerical Analysis Of Anti-cavitation Of Centrifugal Pump Based On Jet Pump

Centrifugal pump is widely used in industry as fluid machinery equipment,but due to its internal structure,when the fluid passes through in the centrifugal pump impeller,it causes pressure drop along the direction of the radius,and reaches the lowest point of pressure at the maximum radius of curvature.Especially when pumping high temperature saturated water,it is the most prone to cavitation.In order to solve the cavitation problem of centrifugal pump,it can be improved by pressing the pump inlet or reducing the temperature of the fluid medium.The jet pump is used to provide the anti-cavitation head before the centrifugal pump,and the centrifugal pump anti-cavitation device can be used to transport high temperature saturated water.The jet pump has some advantages of simple structure,no rotating parts,convenient manufacture,etc.It utilizes the turbulent diffusion of the jet to carry out mass transfer and energy transfer,and two fluids that the high and low pressure can be mixed to obtain a medium pressure fluid.The high pressure fluid can pressurize the low pressure fluid and does not directly consume mechanical energy.The connection system between the jet pump and other equipment is also relatively simple,so it is widely used in engineering.In this paper,the commonly used CFD software Fluent is used to study and analyze the performance and internal cavitation of jet pump.Model the designed jet pump structure,divide the grid in ICEM and import Fluent for numerical calculation.The main research contents of this paper include the following points:1、The working principle and the derivation of the performance equation of the jet pump are briefly introduced.Designed and simulated the jet pump structure in the centrifugal pump anti-cavitation device.Under the different working conditions,studying the pressure ratio and efficiency of the jet pump at different working pressure and the ejector pressure;and under different structural parameters,changing the area ratio and throat mouth distance respectively,observe the impact on the performance of jet pump.Analyze the effect on the flow ratio when the working fluid and the mixed fluid of the jet pump are respectively lowered to different temperatures.2、Exploring the effects of working parameters and structural parameters on jet pump cavitation.The influence of different working pressures and ejector pressures on the jet pump internal cavitation degree were investigated;and the effects of different area ratios and throat distances on the internal cavitation of the jet pump were investigated.When the working section and the mixed diffuser section of the jet pump are lowed to different temperatures respectively,observe the improvement of the jet pump internal cavitation degree.3、Analyze the performance of the centrifugal pump anti-cavitation device.According to the performance equations of the jet pump and the centrifugal pump and the cavitation conditions,the performance equation and performance curve of the centrifugal pump anti-cavitation device are obtained,and the maximum device flow rate and efficiency which can be achieved under different working conditions are analyzed.