中文摘要：

为研究超声振动对电火花铣削间隙流场的作用，根据流场理论将超声振动辅助电火花铣削间隙流场简化为二维流场，建立间隙流场动力学基本方程并推导出间隙流场在x和y方向的压力变化方程。通过Fluent有限元软件建立二维轴对称旋转仿真模型，验证该方程的正确性。分析了间隙流场交变压力的作用，并进行实验验证。研究结果表明：在超声振动的作用下，加工间隙中电介质沿x和y方向超声频率周期性变化的压力增强了空穴作用，促进了电介质的循环，减少了短路和电弧放电，提高了加工过程的稳定性和加工效率，进而提高工件材料去除率，同时能够减小火花放电凹坑深度，使工件加工表面的熔融金属铺展得更均匀，从而降低工件加工表面粗糙度。

英文摘要：

To study the effects of ultrasonic vibration on flow field in the interelectrode gap ol electrodischarge milling, a theoretical model was built based on fluid dynamics theory where the dynamics equation in the flow field was established and the pressure equations along x and y directions were derived as well by simplifying the flow field to a two-dimensional （2D） one. These models were veri fled by an axisymmetric rotate 2D simulation model developed by the finite element analysis software FLUENT. The effects of alternative pressure in the flow field were analyzed and the verification ex- periments were carried out. Results show that the pressure of liquid along x and y directions in the flow field changes periodically at ultrasonic frequency because of the effects of ultrasonic vibration, which makes cavitation effect enhanced. Meanwhile the liquid flow behavior is improved substantially, the probability of short circuit and arc discharge is reduced, the machining stability and efficiency are improved,and thus the material removal rate of workpiece is enhanced. At the same time electric ero- sion pit depth is reduced,which in turn makes the molten metal on workpiece spread out more evenly, and finally the surface roughness of workpiece is decreased correspondingly.