压力扰动下气膜浮环密封的瞬态稳定性研究

Transient stability of air film floating ring seal under pressure disturbance

针对浮环密封容易因密封气压力的扰动导致性能不稳定,从而发生故障以致设备停产的问题,对受压力扰动下的浮环瞬态密封稳定性和上浮稳定性进行了研究。采用UDF编程以及Fluent软件,建立了浮环密封气膜瞬态研究模型;通过提取稳态运行时的结果,设定受扰瞬态模拟的初始值,采取调整时间步长的方法使迭代计算结果收敛,同时对比和分析了不同精度网格模拟结果验证其无关性;并进一步地研究了正弦压力扰动下浮环瞬态密封性能及瞬态上浮性能的变化规律,通过分析不同结构参数大小的浮环受扰结果,探究了浮环间隙及节流长度与瞬态稳定性的内在联系。研究结果表明:在正弦压力扰动下,浮环间隙越大瞬态密封稳定性能越差,间隙为0.013 mm时,密封受扰瞬态稳定性最好;浮环节流长度增加,压力扰动下的瞬态泄漏量波动会减小,而瞬态上浮力波动会增大,但当节流长度超过5 mm后,稳定性基本不再劣化。设计时可尽量减小间隙并适当增加节流长度以增强浮环瞬态稳定性。

Aiming at the problem that the performance of floating ring seal was unstable due to the disturbance of seal gas pressure,the transient sealing stability and floating stability of floating ring under pressure disturbance were studied.The transient research model of floating ring seal gas film was established by UDF programming and Fluent software.The initial value of the disturbed transient simulation was set by the results of steady-state operation,the method of adjusting the time step was adopted to make the iterative results converge,and the grid simulation results with different accuracy were compared and analyzed to verify its independence.The variation law of transient sealing performance and transient floating performance of floating ring under sinusoidal pressure disturbance was researched,and the internal relationships of the floating ring clearance,throttle length and transient stability were explored.The results indicate that under the sinusoidal pressure disturbance,the larger the gap of the floating ring is,the worse the stability of the transient seal of the floating ring is.When the clearance is 0.013 mm,the sealing transient stability under disturbance is the best.When the flow length of the floating link increases,the fluctuation of transient leakage under pressure disturbance can decrease,while the fluctuation of transient upper buoyancy can increase.However,when the throttling length exceeds 5 mm,the stability can not basically deteriorate.Therefore,the gap can be reduced and the throttling length can be increased to enhance the transient stability of the floating ring.