摘要
为提高软性磨粒流切削的效能,研究了利用超声空化作用加快材料去除的方法。在分析磨粒抛光试验和计算流体动力学仿真结果的基础上,提出并验证磨粒碰撞壁面的动能是影响切削效率主要因素的假设;根据对超声空化气泡溃灭,及其在外围水域中冲击波形成与传播的研究结果,分析气泡溃灭在推动磨粒改变其动能时所起的增强湍流效果的作用。在此基础上搭建了超声辅助磨粒流试验装置,以表面覆有氧化层的硅片为试验对象,根据其表面氧化层的去除情况,分析超声空化对硅片表面材料去除能力的影响,并在磨粒流加工无氧化层硅片表面的试验中,观察到超声空化对磨粒流切削的显著影响。验证了超声空化能使磨粒流中的磨粒的动能发生改变,从而起到提高切削效率和提高表面质量的作用,以期为超声波作用下磨粒流加工工艺的改进提供参考。
The method of material removal by ultrasonic cavitation was studied to improve the efficiency of soft abrasive flow machining. Soft abrasive flow machining uses water as the carrier, and the actual processing effect is achieved by abrasive. The uneven peak and valley structure of the machined surface is impacted by a large number of abrasive particles. Those molecules at the high positions of the workpiece surface are more likely to slip or fall apart after collision. First of all, because of the probability of its impact, the molecule of the top in the collision will get more energy to escape from the original position. After a large amount of impact, the structure of the peak and valley tends to be smooth and the surface roughness decreases. The processing efficiency is determined by the kinetic energy of abrasive particles impinging on the wall of the workpiece. Based on the analysis of the abrasive particle polishing experiments and computational fluid dynamics simulation, it was proposed and verified that the kinetic energy of abrasive grain impacting the wall was the main factor affecting the cutting efficiency. When the ultrasonic wave passes through the water, the liquid is no longer a kind of incompressible fluid, and the density of particles varies with sound waves. Bubbles will appear in the water, and the size of bubble will be changed by the ultrasonic wave. The modified Rayleigh-plesset equation with time. Ultrasonic cavitation occurs when the bubble of motion can be used to calculate the variation of bubble diameter diameter is reduced to zero. The actual observation and theoretical calculation indicate that the collapse of the bubble in its interior will produce high temperature and pressure, which triggers a series of complex physical and chemical phenomena. According to the study of ultrasonic cavitation bubble collapse, and the research results of the peripheral water shock wave formation and its propagation, the role of bubble collapse in the change of abrasive particle kinetic energy was anal
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2017年第12期82-90,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金资助项目(51575494
51375446)
浙江省自然科学基金重点项目(LZ14E050001)
浙江省杰出青年科学基金项目(LR16E050001)
关键词
超声
空化
磨削
软性磨粒流
三相流
磨粒运动
ultrasonics
cavitation
machining
soft abrasive flow
three phase flow
abrasive grain movement
