Large Eddy Numerical Simulation And Experimental Study Of Special Inner Surface Of Abrasive Flow Machining

Abrasive flow machining(AFM)technology is a new type of precision machining technology.Due to its unique rheological properties,it can process any complex structure and size parts to meet the requirements that conventional machining cannot meet.In the fields of precision manufacturing,special inner surface workpiece tend to be used due to the speciality of application environment.Therefore,it is of great application value to study special inner surface workpiece with AFM.Combined with the turbulent flow characteristics of the abrasive flow,large eddy simulation numerical method is used to numerically analyze the machining process of the abrasive flow.The influence of different sub-grid models on the calculation results is discussed.The cycloid straight channel and the curved flow channel are used as the research object.Static pressure,dynamic pressure,velocity,wall shear force and vortex distribution of different sub-grid models are analyzed.The results show that The KET sub-grid models can monitor the transient changes of the fluid in real time,capture flow details of the flow field,and the simulation results are more accurate,while the Smagorinsky?WALE and WMLES models have poorer numerical analysis results.By selecting the KET sub-grid model,the numerical analysis of the abrasive flow of the spiral flow channel from different inlet pressures and abrasive concentrations is carried out to explore polishing law.Taking the straight channel with special inner surface as the test workpiece,and the orthogonal test was carried out.The results showed that:after the abrasive flow processing,the surface roughness of the workpiece is reduced,and surface impurities and burrs are effectively removed,and the surface quality is significantly improved.The surface roughness Ra at the exit is slightly larger than the inlet,and the uniformity is slightly insufficient.According to the experimental data,the orthogonal test range analysis and analysis of variance were carried out,and the optimal process parameters of AFM were obtained.The regression analysis was carried out by means of multiple linear regression and polynomial regression.The results denote that the former is more fitting than the latter,indicating the former of regression equation is more pronounced and better.The numerical analysis of process of the abrasive flow machining was carried out by using the large eddy simulation method,and the best sub-grid model was determined,the law of abrasive flow machining was revealed.Through the processing experiment to the workpiece,the optimal polishing parameters of the abrasive flow were determined,which provided data support for the actual production and processing.