负错位密封流动特性研究

Research on Flow Characteristics of Negative Dislocated Seal

随着旋转机械工作介质向高参数方向发展,密封气流激振力成为影响旋转机械转子稳定性的重要因素之一。介质参数提高后,由密封流体动压产生的气体轴承效应增强,密封气流激振力增大。借鉴错位轴承理论,提出一种负错位密封结构,可降低流体动压效应,抑制密封气流激振力。应用CFD技术建立负错位密封与传统圆形密封流场特性求解模型,分析比较2种密封形式周向压力分布特性的差异,研究错位率、转速、偏心、压比等因素对2种密封形式气流力的影响规律。研究结果表明,负错位密封与传统圆形密封泄漏特性相当;与传统圆形密封相比,负错位密封周向压力差小,气流激振力小,负错位密封稳定性好。

With the development of rotating machine operating parameters, the air induced force generates in seals is increasingly becoming one of the most important factors to influence the stability of the rotor system. Air induced force that increases as gas bearing action generates from hydrodynamic in seal becomes bigger with the rotating machine operating parameters intensifying. The paper presented a kind of negative dislocated seal based on the dislocated bearing theory, it can eliminate hydrodynamic action and reduce air induced force. The computational fluid dynamics model for the flow field characteristic of the negative dislocated seal and traditional round seal was set up. The paper relatively analyzed the flow field characteristic difference for the two types of seals, and the influence factors of dislocate ratio, speed, eccentricity, pressure ratio, preswirl were investigated. Numerical results show that the leakage between the negative dislocated seal and traditional round seal is almost equivalent, the negative dislocated seal has less fluid-induced force and better stability.