单向特斯拉环形密封泄漏控制方法研究

Research on Leakage Control Method of Unidirectional Tesla Annular Seal

针对透平机械动静间隙工质泄漏问题,提出新型单向特斯拉环形密封,建立特斯拉环形密封三维模型,采用计算流体力学方法研究特斯拉喷嘴几何结构(轴向数量、分流角、回转直径、喷嘴直径)与运行参数(压比、转速)对密封泄漏特性的影响。结果表明:特斯拉环形密封可以有效降低密封出口流速,抑制密封泄漏,最高可使泄漏量降低15.7%;高压比、高转速下特斯拉环形密封抑制泄漏效果更佳;轴向数目和喷嘴直径都存在一个最佳值,使特斯拉环形密封出口流速最小,泄漏量最低;随分流角减小,特斯拉环形密封出口流速与泄漏量减小;回转直径较小时,对特斯拉环形密封出口流速与泄漏量影响小,但超过喷嘴直径2倍后会使出口流速与泄漏量小幅回升。

To address the working medium leakage problem of turbomachinery static and dynamic gap,a new unidirectional Tesla annular seal was proposed,a three-dimensional model of Tesla annular seal was established,and the influence of Tesla nozzle geometry including axial number,diversion angle,rotation diameter and nozzle diameter and operating parameters including pressure ratio and rotational speed on the seal leakage characteristics was studied by computational fluid dynamics(CFD)method.Results show that the Tesla annular seal can effectively reduce the seal outlet velocity and suppress the seal leakage flowrate up to 15.7%;the Tesla annular seal has better leakage suppression effect at high pressure ratio and high rotational speed;there is an optimum value for both axial number and nozzle diameter,which makes the Tesla annular seal outlet velocity the smallest and leakage flowrate the lowest;as the diversion angle decreases,the Tesla annular seal outlet velocity and leakage flowrate decrease;a small rotary diameter has little impact on the Tesla annular seal outlet velocity and leakage flowrate,but more than two times the diameter of the nozzle will cause the outlet velocity and leakage flowrate to rise slightly.