阀芯微观表面对阀间隙微流动影响的研究

Study on the Effect of Spool's Microscopic Surface on Micro-flow in Valve-gap

运用分形理论,研究阀芯微观表面的分形特征。采用W eierstrass-Mandelbrot函数对阀芯微观表面轮廓进行表征;通过结构函数与尺度符合幂律关系,说明液压阀微观表面具有分形特征。运用分形表征曲线,建立微观阀间隙二维横截面模型,使用FLUENT流体软件对具有粗糙表面阀腔间隙的流场进行数值模拟,并且与理想光滑表面的模拟结果进行对比分析。研究结果表明,粗糙的阀间隙所形成的压力降明显大于理想光滑表面所形成的压力降。对阀芯进行改进,增加环形槽。模拟结果表明,带有环形槽的阀芯既能满足粗糙度要求,又能起到比较好的密封保压作用。

The fractal characteristics of surface spool＇s microscopic surface were studied by fractal theory.The Weierstrass-Mandelbrot function was introduced to characterize the surface spool＇s microscopic surface,its fractal characteristics was certificated by the structure function and scale consistent with Power-Law.The two-dimensional cross-section model of the valve-gap was established,the flow field of the rough valve-gap was simulated by FLUENT and the result was compared with the ideal smooth valve-gap.The results show that the pressure drop formed by the rough valve-gap is significantly greater than by the ideal smooth valve-gap.The spool was improved by adding the ring groove.The simulated results show that the spool with the ring groove can meet the requirement of the roughness,and also can play a good role in sealing and pressure-maintaining.