| ECM is an advanced technology.Its main principle is to change the elemental valence according to the electron transfer between the anode and the cathode.The change of valence of elements causes the dissolution of metals in electrolyte.In this paper,film cooling holes are machined by tube electrodes,and the variation trend of side clearance and material removal rate with processing voltage U,electrolyte inlet pressure P and feed rate f is obtained..The variation of hydrogen volume fraction and electrolyte temperature with machining voltage,electrolyte inlet pressure and electrode feed rate during processing was studied.This paper mainly studies the following aspects:(1)The influence of U,P and f parameters on Δs and MRR is obtained by single factor test method when other process parameters remain unchanged,and the reasons for the influence are simply analyzed.(2)According to the principle of gas-liquid two-phase flow in ECM,the influence of process parameters on the hydrogen gas integral in the interelectrode gap was simulated.The volume fraction distribution of hydrogen in the interelectrode gap and the influence of processing voltage,electrolyte inlet pressure and electrode feed speed on the integral fraction of hydrogen in the interelectrode gap are simulated and analyzed.The effect of hydrogen gas integral on the conductivity of electrolyte was further analyzed,and the mechanism of the effect of hydrogen gas integral on the machining accuracy of cooling hole and material removal rate was obtained.The simulation results show that the volume fraction of hydrogen in the gap presents a "M" distribution,and increases with the voltage and feed speed,and decreases with the electrolyte inlet pressure.(3)According to the heat source and heat transfer mode during the electrolysis process,the influence of various process parameters on the temperature field of the electrolyte was simulated.The simulation results show that the electrolyte temperature increases with the increase of processing voltage and electrode feed rate,and decreases with the increase of inlet pressure.(4)The single-factor test method is used to obtain the side gap and material erosion rate of the cooling holes.Combined with the simulation analysis results of the previous two chapters,the following conclusions are drawn: only change the processing voltage,the volume fraction of hydrogen most affects the processing effect;only change the electrolyte inlet pressure,the electrolyte temperature most affects the processing effect;only change the electrode feed rate,the volume fraction of hydrogen most affects the processing effect.(5)Based on response surface methodology,the processing parameters were optimized by using Design-Expert software,and the optimal parameters combination was obtained,and the experimental verification was carried out. |
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