Study On The Effect Of Flow State Of Grinding Fluid On Grinding Effect In The Process Of Precision Grinding

In the grinding process,the grinding wheel and the workpiece cutting motion will produce high temperature in the grinding zone,which seriously affects the quality,efficiency and precision of the grinding.Therefore,it is necessary to spray the grinding fluid into the grinding zone,and take the heat away to achieve the purpose of cooling,lubrication,cleaning,antirust etc.However,the air flow field which is formed by the rotating grinding wheel to drive the surrounding air movement hinders the grinding fluid from entering the grinding zone,which makes the grinding fluid less than the proper performance.To this end,operation workers often use a lot of grinding fluid.Which reduces the efficiency of grinding fluid,and increased the cost of grinding,and the harmful substances in the grinding fluid can harm the environment and human beings.The grinding fluid has great influence on the grinding quality in the process of grinding.In order to find the root cause of the effective use of the grinding fluid,put forward a solution.set the best supply parameters of grinding fluid.The air flow field and air-liquid two-phase flow field as the research object in precision shaping grinding zone,to change the effect of grinding air flow field and air-liquid two-phase flow field factors as a means,based on the theory of fluid mechanics.building model by CFD methods,using FLUENT software to numerical simulation calculation,get the grinding zone air flow field and air-liquid two phase flow field distribution and analysis and research,the correctness of the numerical simulation results is verified by the precision forming grinding experiment.get the following conclusion:(1)There is a gas barrier layer on the surface of the grinding wheel and a return flow on the surface of the work piece,which can hinder the grinding fluid into the grinding zone;The return flow on the surface of the workpiece is caused by the difference of the positive and negative pressure at the two sides of the minimum gap;Analysis on flow field strengh of each position in the grinding zone,obtain the weakest of the middle strength and the lea st hindering effect of grinding fluid;The velocity and the dynamic pressure of the air flow field in the grinding zone have reached the maximum in the minimum gap;The maximum velocity and maximum dynamic pressure of air flow decreases with the decrease o f the minimum gap in the grinding zone,the air barrier layer and the return flow intensity of the moving air is enhanced with the decrease of the minimum gap,and the hindering effect of grinding fluid is enhanced with the decrease of the minimum gap;The maximum value of the grinding zone flow field velocity,dynamic pressure,the intensity of the air barrier layer and return flow are increased with the increase of the rotational speed of the grinding wheel,hinder grinding fluid with the wheel speed increase large increases,hindering effect of grinding fluid with the increase of the wheel speed increases;The optimum jet velocity of the grinding fluid should be changed according to the change of the grinding wheel speed.(2)We propose a method to determine the full extent of the grinding fluid in the grinding zone by analyzing grinding fluid volume fraction of the surface of the work piece;The dynamic pressure and the velocity of air-liquid two-phase flow are changed drastically in the grinding zone,and reached a maximum at the minimum gap;Influence of different grinding fluid jet position on the air-liquid two-phase flow field,and the optimum jet position of the middle part is obtained;Analyzing the influence of the grinding fluid supply time o n the air-liquid two-phase flow field,the upper grinding fluid which breaks through the air barrier is driven by the air prior to the other position into the grinding zone;The analysis of different influence of jet velocity on the air-liquid two-phase flow field,obtained in sufficient supply of grinding fluid,the grinding fluid jet velocity as small as possible,and to find the optimum jet velocity.(3)The degree of grinding fluid is supplied through experiments,without grinding fluid or grinding fluid supply shortage,the workpiece appear burns and other bad phenomenon and found the 1m/s jet velocity of the grinding fluid supplying the full extent of the dividing line;By grinding fluid jet locations experiment,compared to other locations grinding fluid is injected,the middle part of the jet grinding fluid through the grinding process of the workpiece surface finish high,for the optimum jet position;By grinding fluid jet velocity experiments under grinding fluid supply is insufficient,compared to other grinding fluid jet velocity,1m/s speed grinding fluid jet maximum utilization,for the optimum injection rate;In precision shaping grinding experiment.through under different scheme of the experimental results compared with the results of numerical simulation,it is proved that the optimum supply parameter of grinding fluid is calculated by the numerical simulation of the flow field in the grinding zone.