螺旋槽干气密封气膜刚度测试与稳定性分析

干气密封的关键技术是动压效应和稳定性问题，而气膜刚度是影响振动稳定性的主要参数之一。采用高精度改进型的电涡流微型传感器和Labview软件，并采用一系列的抗干扰措施，建立了螺旋槽干气密封的测试系统。通过测量干气密封的轴向静环振幅和轴向气膜振幅，而获得气膜刚度，并分析了其气膜振动的稳定性。试验研究表明：随着转速的增加和压力的升高，气膜刚度随之增大，气膜稳定性越好。本例中：压力变化范围为0.2-0.5MPa，转速变化范围为500 - 3000 r/min，得气膜刚度值的变化范围为0.01 - 0.03 KN/μm，且气膜刚度分别与压力和转速基本成线性关系；试验中测试了三种不同螺旋角的样机，得螺旋角为74°时，气膜刚度最大，气膜稳定性最好，选取合适的螺旋角可增加气膜的稳定性，从而对结构参数的优化提供了指导。

The Test and Stability Analysis of Gas Membrane Stiffness On Spiral Grooved Dry Gas Seal

The key technology of dry gas seal is dynamic pressure effect and stability , and gas film stiffness is one of the main parameters influencing the vibration stability. Employing high precision improved version of the eddy current miniature sensor and Labview software, the test system of spiral grooved dry gas seal was established by a series of anti-jamming measures. Through the measurement of axial amplitude of gas film and stationary seal ring, gas film stiffness was obtained, and then the stability of gas film vibration was analyzed. Experimental research shows the following fact, that when revolving speed and pressure increase, gas film stiffness increases and the stability of gas film vibration is better. In the example, gas film stiffness value range is 0.01-0.03 KN/μm when pressure range is 0.2-0.5MPa and the change range of revolving speed is 500-3000 r/min. Gas film stiffness and pressure are a kind of fundamental linear relationship, and the same situation goes with gas film stiffness and revolving speed. Three different spiral angle samples were tested in the experiment, which turns out that gas film stiffness value will be the biggest and gas film stability will be the best when spiral angle is 74 degrees. Moreover, selecting the suitable spiral angle can increase the stability of gas film, and provide guidance for structural parameters optimization.