高能脉冲态气液辅助电解加工高深宽比微结构的基础研究

Manufacturing technologies of surface microstructures have shown great application value in fields of pistons, bearing, medical parts and so on. For the current issues of electrolytic products discharge difficulties and uneven anodic dissolution due to irregular distribution of the passivation film during electrochemical machining of high aspect ratio microstructures, this project proposes a new technology called high energy pulse state gas-liquid assisted electrochemical machining which means generating high energy shock waves to accelerate the discharge electrolysis products and uniform removal of passive film. The high energy pulsed state gas-liquid assisted electrochemical machining process is the research basis of this project and the flow channels on bipolar plate is the research object. In theoretical research, the lattice Boltzmann method (LBM) will be used to describe the dynamic behaviors of bubbles in the flow field and the influence of the interaction between bubbles on the macroscopic flow field under meso scale, the multi-scale flow field numerical models of high energy pulsed gas-liquid assisted electrochemical machining will be established. Based on the interface mechanics and contact mechanics, the mechanical behaviors of the pulsed gas-liquid two-phase flow for passivation film scouring will be studied. In the key technological reseach, the high energy pulsed gas-liquid assisted electrochemical machining test device will be developed. Based on the theoretical research and experimental analysis, the rule of the process will be summarized and the basic technologies of high energy pulse state gas liquid assisted electrochemical machining will be established. This work will be greatly useful for developing the application of electrochemical machining in the manufacturing field of high aspect ratio micro structure.

表面微结构加工技术已在活塞、轴承、医疗器件等领域中展现出巨大的应用价值。本课题针对高深宽比微结构电解加工中存在电解产物排出困难与钝化膜分布不规则造成阳极溶解不均匀的问题，提出了高能脉冲态气液辅助电解加工新工艺，通过产生高能量脉冲态气液冲击波来加速电解产物的排出与钝化膜的均匀去除。本项目将以高能脉冲态气液辅助电解加工为研究基础，以双极板表面高深宽比流道为研究对象。在理论上，拟采用格子玻尔兹曼方法（LBM）在介观尺度上对脉冲态流场内气泡群的运动行为，及气泡间相互作用对宏观流场的影响进行描述，建立高能脉冲态气液作用下流场的多尺度耦合模型。基于界面力学和接触力学研究脉冲态气液两相流冲刷钝化膜的作用机制。在关键技术上，研制高能脉冲态气液辅助电解加工装置。综合理论分析与试验研究，归纳工艺规律，建立高能脉冲态气液辅助电解加工技术基础。本项目的研究对促进电解加工在高深宽比微结构制造领域的应用具有重要意义。

表面微结构加工技术已在活塞、轴承、医疗器件等领域中展现出巨大的应用价值。本课题针对电解加工中存在电解产物排出困难与钝化膜分布不规则造成阳极溶解不均匀的问题，提出了高能脉冲态气液辅助电解加工新工艺。.本课题以高能脉冲态气液辅助电解加工工艺为基础，系统地研究了三种类型（空化射流、静液式与主动补液式）高能脉冲态气液辅助掩膜电解加工微结构新工艺。根据该工艺特点，从三个方面开展研究：①在理论方面，系统地研究了几种典型材料（GCr15、单晶SiC）的电化学特性，设计了电解加工实时同步观测装置，采用高速摄像仪与电流传感器同步采样方法，详细研究了钝化膜的形成过程（钝化周期与钝化膜形貌）与材料特性；通过有限元方法（水平集、相场法）建立了高能脉冲态气体作用下的电解加工间隙区域流场理论模型，分析了不同工艺参数（脉冲气体流量、脉冲气体频率、脉冲气体占空比等）条件下高能脉冲气体对流场的影响规律。仿真结果表明，在合适参数条件下，脉冲气体作用于加工区域的流场会循环出现“液相→气液两相→气相”的流场形态，从而有助于电解加工区域电解液的快速更新，提高了加工区域的流速与流场均匀性；②在关键技术方面，研制了集机床、电源、工艺参数控制于一体、较为完善的数字化脉冲态气液辅助电解加工系统，实现了对电源参数和其他参数（运动轴、电解液压力、电解液流量、脉冲气体压力、脉冲气体频率、脉冲气体占空比等）控制的集成化，并开发了专用控制系统软件；③工艺试验方面，针对三种类型（空化射流、静液式与主动补液式）高能脉冲态气液辅助掩膜电解加工微结构工艺进行了基础研究，分析了脉冲气体参数对加工精度与加工均匀性的影响规律及工艺措施，初步验证了高能脉冲态气体辅助电解加工工艺的可行性，试验结果表明高能脉冲气体有助于促进电解加工区域的电解产物的快速排除，从而提高电解加工的稳定性。