Numerical Simulation Of Flow Field And Temperature Field Of The New Type Hybrid Rotary Table Based On CFD

As a functional component of large and heavy precision machine tools,operation precision of the rotary table has a great influence on the processing accuracy,running stability and working life of the whole machine.Therefore,it is of great significance to improve the kinematic accuracy of rotary worktable for the overall performance of precision machine tools.Because of the large size of the large rotary table,it is easy to crawl when starting and low speed running,and the motion stability is poor.Moreover,the heat generated by friction can't be passed through in time,resulting in the high temperature rise of the local oil film,the decrease of viscosity,the difficulty in the establishment of the oil film and the deterioration of the lubrication condition,which eventually leads to the decline of the performance of the turntable.In view of the problems of the rotary table,a new design concept of the spiral oil wedge hydrostatic turntable is put forward.Through the combination of "differential" and "spiral flow",the stability of large turntable is improved and the problem of heat dissipation is solved.ANSYS FLUENT is used to simulate the complex flow field and temperature field of the rotary table,and the oil chamber structure is reasonably optimized.Finally,the experimental results and the simulation results are compared and analyzed.The specific content of the work is as follows:Firstly,the structure and working principle of the new rotary table is introduced.The finite element structure model of the oil cavity is established by Pro/Engineer.The unstructured grid is divided by ICEM CFD,and the basic control equation is established.The model hypothesis and the initial boundary conditions are determined,and the related software is briefly introduced.Secondly,using the CFD software based on the Navier-Stokes equations to simulate the complex flow conditions of the rotary table.The oil film pressure field,temperature field,velocity field,velocity vector,and streamline distribution are obtained.The analysis and discussion of the changes in oil film pressure,temperature rise,and flow streamline at various speeds and film thicknesses of the turntable are discussed.The relationship between the pressure peak at the oil wedge and the maximum temperature rise of the oil film with the rotation speed and the oil film thickness was fitted.Thirdly,the problem of negative pressure and insufficient supply of dynamic pressure screw oil wedge in the external groove area of static pressure chamber is studied and three methods are put forward.The structure of the oil chamber is optimized,and the performance of the rotary table is improved.Finally,a new experimental platform is built,and the experimental principle and scheme and the composition of the experimental system and the layout of various sensors are introduced.The signals of eddy current sensors and pressure sensors under different working conditions are collected and ideal low pass filtering is applied to them.By comparing with the simulation results,it is found that the experimental results are in good agreement with the CFD simulation results,which confirms the reliability of the simulation results and the feasibility of the method.Through the study of the internal flow field and temperature field of the new turntable,a new way is provided to improve the operation precision of the large rotary table and solve the heat dissipation problem of the large rotary table.It is of great significance to the development of heavy and heavy equipment manufacturing industry in China,laying a theoretical foundation for the design of ultra large precision dynamic and hydrostatic turntable.