Flow field characteristics analysis of interelectrode gap in electrochemical machining of film cooling holes

Abstract

Electrochemical machining (ECM) is an important method to drill film cooling holes in difficult-to-machine materials such as high-temperature nickel-based alloy. However, physical field parameters of ECM, such as flow field characteristics and temperature field distribution in the interelectrode gap, cannot be directly monitored, which makes it difficult to improve the accuracy of ECM. In this paper, the effect of processing voltage, electrolyte inlet pressure, and electrode feed rate on machining accuracy was studied through experiments. According to the gas–liquid two-phase flow theory and mathematical model of convective heat transfer, the volume fraction of hydrogen and electrolyte temperature field were simulated and analyzed by COMSOL Multiphysics software. The results indicate that the electrolyte temperature plays a dominant role in all factors affecting the processing effects when only the processing voltage or electrolyte inlet pressure changes. When only the electrode feed rate changes, volume fraction of hydrogen dominates the effects. This has guiding significance for practical production, and can improve the accuracy of ECM by controlling the temperature of the electrolyte and the volume fraction of hydrogen.