CFD Analysis Of Fluid Field For Electrochemical Machining Cooling Holes Of Nickel-based Superalloy

With the growing recognition of electrochemical machining process characteristics,electrochemical machining process by tube electrodes has become the important processing technology of aircraft engine's cooling holes machining field.The forming rule of the cooling hole of the tube electrode is not only affected by the electric field and electrochemical dissolution field,but also with the electrolyte fluid field.With ?0.9mm~?1.6mm cooling turbine blade hole as the research object,based on the experimental results and the data of the cooling process of the tube electrode,the real three-dimensional flow field model of the cooling hole was established and the CFD fluid field was simulated.In view of the existing problems of the influence of the fluid field distribution on the electrochemical machining of cooling hole,this paper mainly completed the following several aspects of the research:1.Based on the important process factors and the characteristics of electrochemical machining by tube electrodes,cooling holes 's machining test was designed mainly from the three aspects of the electrolyte inlet pressure,machining voltage and electrode feed rate.Through analyzing and monitoring the test result,the influence of three process factors on the forming accuracy of cooling holes by the tube electrodes was determined.2.Based on the gas liquid two phase flow field characteristics of the cooling hole by shape tube electrochemical machining,the gas-liquid two phase flow model of flow field in the machining gap was simulated by COMSOL.Simulated the gas phase,liquid phase distribution at different processing time.Simulation results shown that the flow field in the machining gap caused by gas phase irregularly distributed irregularly distributed current density,electrolyte conductivity changed,affect the cooling hole forming accuracy.3.The cooling holes were sliced on 5-axis NC machining center,each layer geometry size was measured.Using CAD technology to reconstruct the real 3 D fluid field model under different processing conditions.The fluid velocity field,fluid pressure and turbulence distribution in the electrochemical machining area were analyzed using FLUENT.The basic relationship between electrolyte inlet pressure,machining voltage and electrode feed rate with the fluid field was discussed.The electrolyte inlet pressure had remarkable effects on fluid velocity field.When the pressure is near 0.4MPa,the fluid field was high-speed,steady and uniform.Effect of machining voltage on fluid turbulence distribution sensitivity.The pressure distribution of electrolyte fluid field became uniform,negative pressure area was zero.Based on the results of CFD analysis,the parameters of the experiments were adjusted and optimization experiments were done.Through the analysis of results of basic experiments and optimization experiments,the optimal process parameters were obtained.