等边三角形微孔端面机械密封多楔现象对性能的影响
Effect of Multi-wedge on Sealing Performance in Mechanical Seal with Equilateral Triangular Dimples
作者：吉华(四川大学 化学工程学院, 四川 成都 610065)；王彦镐(四川大学 化学工程学院, 四川 成都 610065)；战琳月(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)；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)；WANG Yanhao(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)；ZHAN Linyue(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)；JIANG Sen(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)；CHEN Zhi(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)
收稿日期：2018-01-29 年卷（期）页码：2019,51(2):168-175
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：机械密封;等边三角形微孔;多楔现象;泄漏率;开启力
Key words：mechanic seal;equilateral triangular dimples;multi-wedge;leakage rate;load-carrying capacity
基金项目：
中文摘要
微孔端面机械密封是通过设计改变微孔的几何特性以期望得到更优的密封性能，但几何特性如何影响密封性能却缺乏机理上的研究和指导。结合流体楔效应理论，采用数值计算的方法，基于Fluent多相流空化模型，针对等边三角形微孔端面机械密封，建立了其中1个微孔周期的间隙流体的3维数值计算模型，研究不同方向角下等边三角形微孔几何特性的改变对泄漏率和开启力的影响。首先，使用了流动因子判定流动状态、网格无关性分析确定网格尺寸、文献计算结果对比等方法，保证了数值计算模型的正确性。然后，结合楔效应理论与压力云图分析，提出了多楔现象，即：等边三角形微孔存在3个性质不同的楔。方向角的变化改变了各楔与密封端面旋转线速度间的夹角，故各楔的性质与强度随方向角的变化而变化。流体流经各楔，会产生不同的楔效应，多楔效应的组合影响了压力分布，最终决定了密封性能。最后，基于多楔现象，研究了等边三角形微孔端面机械密封的泄漏率与开启力。低压差下，方向角α=40 °时泄漏率最小；高压差下，α=110 °时泄漏率最小；增大转速将强化泄漏率的变化趋势。开启力在α∈[0 °,120 °]时，先减小后增大，α=60 °时开启力最小；当α∈[0 °,40 °]及α∈[100 °,120 °]时，开启力随转速增加而增大；当α∈[40 °,100 °]时，开启力随转速增加而减小。
英文摘要
The mechanism of how the geometric features of dimples work on the performance of mechanical seal with micro-dimple has been rarely studied, although the geometric design of dimples is one of the most important means for enhancing the performance. In order treat this problem, based on the multiphase flow cavitation model in fluent, the wedge effect theory and the numerical calculation were employed to develop a three-dimensional numerical model of the lubricant in mechanical seal with equilateral triangular dimples for studying the effect of the geometric features on the leakage rate and the load-carrying capacity at different orientation angles. Firstly, the fluid factor was calculated for the flow pattern check, and the grid independence test of film was conducted for determining the grid size. The simulation result was also compared with the reference in order to ensure the accuracy of calculation model. Secondly, the multi-wedge phenomenon was proposed based on the wedge effect theory and the analysis of pressure contours. The equilateral triangular dimple has three different wedges. The orientation angle changes the angles between each wedge and the rotational velocity of seal face, which determines the character and intensity of the wedges. The cooperation of the three wedge effects influences the pressure distribution, and then determines the sealing performance. Finally, the leakage rate and load-carrying capacity of the mechanical seal with equilateral triangular dimples were studied based on the multi-wedge phenomenon. The leakage rate is minimal when the orientation angleα=40 ° for the low pressure difference, andα=110 ° for the high pressure difference. The increase of velocity enhances the change trend of leakage rate. The load-carrying capacity decreases at first, and then increases whenα∈[0 °,120 °], and is minimal whenα=60 °. With the increase of velocity, the load-carrying capacity increases whenα∈[0 °,40 °] andα∈[100 °,120 °], but decreases whenα∈[40 °,100 °].
【关闭】
