High-speed electrochemical discharge drilling (ECDD) offers substantial benefits for efficient, high-quality fabrication of film cooling holes. One shortfall of this technique is the lack of a visual model for simulations. The determination of optimal machining parameters predominantly depends on trial-and-error methodologies. In order to develop a visual model for simulations, an in-depth analysis of the machining mechanism is necessary. This entails direct observation of the machining phenomena and a thorough understanding of the surface topography evolution processes. The study focuses on machining Ni-based single-crystal materials that are used in turbine blades, employing experiments to investigate the material removal mechanism. Based on the relevant conclusions, a visualized simulation model is developed for the first time. The results show that discharge and electrochemical dissolution occur alternately at the microscopic level. Besides, the discharge in low conductivity solutions is similar to pure electrical discharge drilling (EDD) rather than a gas film discharge. Discrepancies in the elemental distribution of the matrix and recast layer cause changes in the electrochemical dissolution behavior. The current efficiency of the recast layer is significantly lower than that of the matrix. Based on the mechanistic exploration, this study integrates discrete discharge with continuous electrochemical dissolution to construct a visual model of high-speed ECDD, by leveraging a dead grid method and explicit differential. This model can precisely anticipate the distribution of the recast layer and the diameter of the hole, thereby contributing valuable insights towards achieving zero recast layer machining and enhancing the use of ECDD in the aerospace industry.

中文翻译：

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气膜冷却孔高速电化学放电钻孔的洞察：加工现象、形态演化和可视化模拟

高速电化学放电钻孔 (ECDD) 为高效、高质量的薄膜冷却孔制造带来了巨大的好处。该技术的一个缺点是缺乏用于模拟的视觉模型。最佳加工参数的确定主要取决于试错方法。为了开发用于仿真的可视化模型，需要对加工机制进行深入分析。这需要直接观察加工现象并彻底了解表面形貌演变过程。该研究的重点是加工涡轮叶片中使用的镍基单晶材料，通过实验研究材料去除机制。基于相关结论，首次开发了可视化仿真模型。结果表明，放电和电化学溶解在微观水平上交替发生。此外，低电导率溶液中的放电类似于纯放电钻孔（EDD），而不是气膜放电。基体和重铸层元素分布的差异会导致电化学溶解行为的变化。重铸层的电流效率明显低于基体。本研究在机理探索的基础上，利用死网格法和显式微分，将离散放电与连续电化学溶解相结合，构建了高速 ECDD 的可视化模型。该模型可以精确预测重铸层的分布​​和孔的直径，从而为实现零重铸层加工和增强 ECDD 在航空航天工业中的使用提供宝贵的见解。