Numerical Simulation And Experimental Study Of Orifice Cavitation Based On Pure Water Medium

In recent years,hydraulic cavitation technology has been widely used in many fluid fields because of its high efficiency,low energy consumption and no secondary pollution.It has become a research hotspot in sewage treatment.Because the cavitation phenomenon in the fluid is microscopic and instantaneous,and the means to characterize the cavitation intensity is relatively single,there is no breakthrough in how to quantitatively analyze the strength change of cavitation effect in the cavitator.In view of this,this paper takes the perforated plate cavitator as the experimental device,adopts the research method of combining numerical simulation and experiment,and takes pure water as the cavitation medium to verify the cavitation characteristics in the perforated plate cavitator from the perspective of water properties.(1)According to the flow characteristics of gas-liquid two-phase flow in the orifice cavitator,the control equation and turbulence model of the fluid in the orifice are analyzed.According to the flow characteristics of the fluid,the flow equation in the orifice cavitator is deduced theoretically.At the same time,considering the shortcomings of the steady-state cavitation model of the fluid,a dynamic cavitation model suitable for gas-liquid two-phase in the orifice is established,It provides a theoretical basis for subsequent simulation.(2)The geometric model of fluid is established by Creo,and it is meshed by ICEM-CFD;The fluid models with different structural parameters are simulated by fluent.The precipitation position of gas core and the distribution of pressure and gas holdup in the flow field are observed with the help of cloud diagram.The gas phase mass flow rate is used as the standard to judge the cavitation intensity,and the effects of orifice thickness,hole number and hole type on orifice cavitation characteristics under different pressure differences are quantitatively analyzed.(3)Combined with the influence of single factor on water properties,an orthogonal test is established to optimize the operating parameters and obtain the optimal experimental operating parameters.Under this parameter,the cavitation effect of orifice plates with different structures is verified.By measuring the conductivity and dissolved oxygen of water samples in the cavitation process,the cavitation intensity in orifice plates with different orifice plate thickness,different number of holes and different hole shapes is characterized,It is found that the cavitation effect of orifice plates with different structural parameters under the pressure difference of 0.2mpa-1mpa is consistent with the numerical simulation,which provides a reference for the research method of orifice cavitation device.