均布圆柱形孔活塞环油膜承载力的解析解和数值计算
Analytical and Numerical Approach of Load Capacity for Piston Ring with Equispaced Cylindrical Dimples
作者：吉华(四川大学 化学工程学院, 四川 成都 610065)；蒋森(四川大学 化学工程学院, 四川 成都 610065)；吴孙珂(四川大学 化学工程学院, 四川 成都 610065)；陈胡炜(四川大学 化学工程学院, 四川 成都 610065)；陈志(四川大学 化学工程学院, 四川 成都 610065)
Author：JI Hua(School of Chemical Eng.,Sichuan Univ., Chengdu 610065, China)；JIANG Sen(School of Chemical Eng.,Sichuan Univ., Chengdu 610065, China)；WU Sunke(School of Chemical Eng.,Sichuan Univ., Chengdu 610065, China)；CHEN Huwei(School of Chemical Eng.,Sichuan Univ., Chengdu 610065, China)；CHEN Zhi(School of Chemical Eng.,Sichuan Univ., Chengdu 610065, China)
收稿日期：2019-01-16 年卷（期）页码：2020,52(3):193-200
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：解析解;承载力;数值模拟;圆形微孔;活塞环
Key words：analytical solution;load capacity;simulation validation;cylindrical dimples;piston ring
基金项目：德阳重点科学技术研究项目（GXCC20180013）
中文摘要
现有对微织构的研究多采用数值法。相比于数值解，解析解有助于简单清楚的表达微孔活塞环润滑性能的主要影响因素和各物理量的潜在关系，提高设计者的认识。基于入口吸入理论和流量连续性条件，对均布无限个圆柱形微孔的活塞环的1维油膜的空化区分布、压力分布和承载力进行了解析计算，并将1维解析解积分得到了1个周期油膜的承载力。解析解表明：均布n个圆柱形微孔活塞环的前n-1孔的压力分布相似，最大压力相等，最大压力与进口压力，孔间间距和空化压力相关，在均布微孔时，孔内最大压力约为进口压力的两倍；第n孔的压力分布和最大压力还与出口压力相关，在均布微孔时，孔内最大压力约为进出口压力之和。同时，还揭示了孔深对空化分布和油膜承载力的影响机理，当孔深大于油膜厚度的一半时，随着孔深的增加，空化区面积减小。使用Fluent软件对均布4个孔的油膜进行了数值模拟，并与解析解作对比。在解析解有解，数值解收敛的范围内，解析计算和数值计算的结果规律一致，解析式能解释数值模拟得到空化区分布、压力分布以及油膜承载力的变化趋势，所获得的在最大油膜承载力时的微孔几何尺寸也与模拟计算一致，油膜承载力的解析解和数值解最大相差10%。
英文摘要
The numerical simulation is mostly employed in the existing studies of micro-texture. Compared with the numerical solution, the analytical solution describes more clearly the influence of main factors on the lubrication performances and the potential relationship between various physical variables in the piston ring with dimples. And it can also improve the designers understanding. Firstly, the cavitation zone, the pressure distribution and the load capacity of one dimensional oil film between the cylinder liner and piston ring with equispaced dimples, are analyzed with the analytical method based on the inlet suction mechanism and flow continuity condition. Secondly, the analytical solution for load capacity of one oil film period is obtained by integrating one-dimensional analytical solution. The analytical solutions show that the pressure distributions of the firstn-1 dimples are similar and the maximum pressures of the firstn-1 dimples is equal, which is decided by the inlet pressure, the distance between dimples and the cavitation pressure, while the pressure distribution and maximum pressure of dimplenare decided by the outlet pressure besides these three factors. When the dimples are equispaced, the maximum pressure is about double inlet pressure in the firstn-1 dimples and about the sum of the inlet and outlet pressures in the dimplen. They also show the influences of dimple depth on the cavitation distribution and the load capacity. When the dimple depth is more than half of the oil film thickness, the area of cavitation zone decreases with the increase of dimple depth. At last, the Fluent software is employed to simulate the oil film with four equispaced dimples. The results of analytical calculation and numerical calculation are consistent. The analytical solutions can explain the cavitation, the pressure distribution and the trend of load capacity in numerical simulation. The same optimal geometric size at the maximum load capacity is obtained with the numerical and the analytical solution, and the difference of load capacity between two solutions is below 10%.
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