涡轮叶片冷却孔电解加工电解液流场CFD分析研究

CFD analysis on electrolyte fluid field for electrochemical machining of blade cooling holes

以航空发动机涡轮叶片常用材料高温镍基合金Inconel718为基材进行气膜冷却孔电解加工试验,通过30组对比试验,以短路次数和单边间隙△_s作为性能评价指标,探讨了加工电压U和电解液浓度ζ对冷却孔加工效率和加工精度的影响规律。基于CFD软件,进一步着重研究了电解液速度及涡流等因素对冷却孔加工的影响规律。CFD分析得出:随着电解液浓度的升高,速度场分布均匀,涡流变化梯度增大,加工稳定性提高,加工精度降低;随着电压的升高,冷却孔锥度变大,加工精度较低,涡流变化较小,当电压较大时,较多气体析出,导致速度场分布不均匀且不连续,加工稳定性变差。

Film cooling holes were obtained by electrochemical machining using Inconel718 nickel-based super-alloy which is commonly used for turbine blade of aero-engine. Under different parameters（ voltage U,concentration of electrolyte ζ）,30 sets of orthogonal experiments were conducted on the machining efficiency and machining accuracy. This paper studies the electrolyte flow rate and eddy currenton electrolyte cooling holes processing accuracy and stability of the law. The results： while the concentration increasing,velocity distribution was uniform and eddy current was various,worse processing stability could be improved and processing forming was worse; while the voltage increased,the taper of cooling hole was increased obviously and processing accuracy was worse. With the higher voltage,the gas bubble evolution introduced the discontinuity and periodic fluctuation of filed fluid,worse processing stability.