基于双自激振荡腔室磨粒流抛光的流体脉冲特性研究

Study on Fluid Pulse Characteristics Based on Abrasive Flow Polishing of Double Self-excited Oscillation Cavity

目的自激振荡脉冲磨粒流抛光方法主要应用于型腔零件内表面的抛光,为进一步增强抛光液的自激振荡脉冲特性,以提高抛光效率,提出一种基于双自激振荡腔室的磨粒流脉冲特性抛光方法。方法利用串联的两个自激振荡腔体,对抛光液的流体脉冲特性进行二次放大,增强抛光液的峰值速度以及湍流动能。利用数值模拟分析双自激振荡腔室的脉冲特性,搭建串联式双自激振荡腔室磨粒流脉冲特性抛光实验平台,实验验证新增一个自激振荡腔室对提高抛光液脉冲特性的有效性。结果仿真结果表明,双自激振荡腔室有增大峰值速度的作用,从单个腔室的66.8 m/s增加到了76.8 m/s。对直径为6 mm的不锈钢管内表面进行抛光的实验结果表明,在相同的实验条件下,加工10 h,采用双自激振荡腔室抛光的工件内表面粗糙度Ra从452 nm降低到了42 nm,且内表面具有显著的镜面效果;而采用单个自激振荡腔室加工的不锈钢管内表面粗糙度Ra降到了100 nm,内表面相对暗淡,还需要继续抛光2 h才能达到42 nm。同时,实验还证明了流体的脉冲特性在流道中存在衰减。结论通过数值模拟与实验分析验证了双腔室自激振荡磨粒流抛光方法的有效性,具有进一步增强抛光液峰值速度及湍动能的效果。为充分利用自激振荡脉冲特性,需要将工件安装在靠近腔体下游出口处。

Self-excited-oscillation pulsed abrasive flow polishing method is mainly used to polish the inner surface of cavity parts.To further improve the polishing efficiency through enhancing self-excited oscillation pulse characteristics of the polishing liquid,a polishing method based on abrasive flow of double self-excited oscillation cavity is proposed.By using the double self-excited oscillation cavities connected in series,the self-excited oscillation pulse characteristics of the polishing fluid were further enhanced,and the peak velocity and turbulent kinetic energy of the polishing fluid were also increased.The pulse characteristics of double self-excited oscillation cavity was analyzed by numerical simulation,and a polishing experimental platform was established for abrasive flow of double self-excited oscillation cavities connected in series.Experiments verified the effectiveness of the double self-excited oscillation cavity to improve the pulse characteristics of the polishing liquid.Simulation results show that the double self-excited oscillation cavity has an effect of increasing the peak velocity,from 66.8 m/s to 76.8 m/s.The experimental results of polishing the inner surface of a 6 mm diameter stainless steel tube show that:under the same experimental conditions,after processing for 10 hours,the roughness Ra of the inner surface of the workpiece polished by the double self-excited oscillation cavity was reduced from 452 nm to 42 nm and the inner surface had a significant mirror effect;while the roughness Ra of the inner surface of the stainless steel tube processed by a single self-excited oscillation cavity was reduced to 100 nm,and the inner surface was relatively dark,and it needed to take another 2 hours for reaching 42 nm.At the same time,the experiment also proves that the pulse characteristics of the fluid was attenuated in the flow channel.The effectiveness of abrasive flow polishing of double self-excited oscillation cavity was proven by numerical simulation and experimental analysis,with the effect of further enhancing the peak fluid velocity and turbulent kinetic energy.In order to make full use of the self-excited oscillation pulse characteristics,the workpiece needs to be installed near the downstream outlet of the cavity.