Analysis Of Influence Of Structure And Parameters On Performance Of High Pressure Water Descaling Nozzle And Optimization

Before hot rolling,the surface of the steel will be heated to produce a layer of iron oxide,which is called the scaly skin.The scaly skin affects the quality of hot rolling,so it must be removed before rolling.The high pressure water descaling technique uses the mechanical impact of high pressure water to remove the scaly skin on the surface of steel,which is an effective method of descaling in steel mills.The descaling nozzle is a device for high pressure water flow,and the jet performance of the nozzle will directly affect the quality of the descaling of the steel.Therefore,by studying the performance of the internal and external flow field of the descaling nozzles,the improved scheme is discussed in this paper,so that the nozzle can get better dynamic pressure distribution to enhance its descaling ability,and at the same time,enhance the service life of the nozzle itself.The main contents of this paper are as follows:(1)Taking the flow field model of the original nozzle as the research object,through the analysis of fluent flow field,the characteristics of the outflow field of the original nozzle are discussed.The selection basis of the best target distance is given,and the function of the guide is analyzed.(2)With the computational fluid dynamics software FLUENT as the basic tool,the characteristics of the external flow field of the scale removal nozzles with different penetration depth,different shrinkage orifice forms and different grooves are discussed.With the same target distance line force length,outlet total pressure and mass flow as the main index,we study the variables in their impact on the performance of jet nozzle.(3)Using the erosion model and discrete phase model in fluent,the influence of nozzle shrinkage port structure on erosion wear of outlet is studied,and the improvement plan is given.By using the user defined function in fluent,the cavitation number of nozzles is made.It is found that the most serious cavitation erosion area near the flow nozzle is found.(4)According to the Quadratic regression accuracy uniform central composite rotatable experimental design,using two multivariate nonlinear regression method fitting the original nozzle outlet orifice area,the contraction angle and cutting function between the external flow field of nozzle and diffuser angle groove.The response surface analysis method was used to discuss the change relationship between the 22 of the above independent variables.Finally,a comprehensive improvement scheme for the nozzle is given on the basis of the original nozzle.