Fundamental Research On Multiphysics Coupling Of Mesoscopic Geometry Structure Of Electrochemical Finishing Interelectrode Gap

Electrochemical finishing can significantly improve the machining quality of mechanical core parts because of its unique processing mechanism and advantages.However,the finishing is carried out under the process of multi-physical field coupling in the mesoscopic gap.During the whole machining process,the mesoscopic geometry of the workpiece surface changes all the time.Among them,the small gap involves a variety of physical and chemical changes,such as the distribution of the current field between the electrodes,the mass transfer between the electrode and the electrolyte,the generation of bubbles and so on,which not only leads to the poor stability of the machining quality of the workpiece but also affects the performance of the workpiece.In order to solve the problem of poor machining quality stability in the process.In this paper,the mesoscopic geometric structure of the workpiece surface is taken as the research object.The simulation model is established and experiments are carried out by COMSOL Multiphysics simulation software.The main research contents are as follows1.The influence of the change of workpiece's mesoscopic geometry on the current field distribution is studied.By analyzing the dynamic characteristics of similarity principle and taking the geometric characteristics of mesoscopic morphology as the research object,the mesoscopic geometric structure model of interpolar gap is established.In the process of machining,the mesoscopic geometric structure of the workpiece surface and the distribution characteristics of fluid field are analyzed.The results show that the distribution characteristics of the current field can reduce the difference of the workpiece's mesoscopic geometry and improve the machining quality.At the same time,the change of the mesoscopic geometric structure of the workpiece surface is due to the difference of current in different positions,so the workpiece is processed macroscopically.2.The influence of different roughness elements on the mesoscale flow is studied.The distribution of the flow field in the spike and arc rough elements is solved by simulation.And the different shapes' effects of rough elements on the flow in the machining area are observed through design experiments.The results show that the flow field produces a vortex in the cavity near the spike rough element,which can improve the phenomenon of liquid shortage in the wave trough,and the passivation film is machined in a certain sense because of the continuous vortex movement of the fluid.Compared with the peak rough element,the flow field uniformity in the circular arc rough element is better.3.The effect of bubble deformation on flow field stability through gas-liquid two-phase flow is studied.The gas-liquid two-phase flow model is established to analyze Characteristics of bubbles.The results show that the changing process of the bubble leads to the uneven velocity of the nearby flow field.And the flow field produces vortex structure around the bubble,which is easy to cause bubbles oscillation and reduce the stability.4.The influence of the interaction of multi-physical fields about finishing is studied.The cathode,anode device and electrolyte circulation system were designed and processed.After then the experimental platform was built.The established model is used to guide the experiment,and the fractal function is used to analyze the morphology of the workpiece before and after processing.The results show that the experimental results are basically consistent with the simulation model.And the model can objectively reflect the coupling relationship between multi-physical fields,so electrochemical finishing can improve the performance of the workpiece.