螺旋槽干气密封压差扰动下的瞬态特性研究

摘要

干气密封的瞬态特性是密封动力学研究中的重要内容,而现有研究主要关注于密封稳态特性的研究.本文针对密封内外压差波动这一典型工况开展仿真分析,研究螺旋槽干气密封在扰动工况下的瞬态特性.计算中,将润滑方程、接触方程与动力学方程耦合求解,以轴向膜厚、角向偏摆角、泄漏率和端面接触载荷为主要指标.结果表明:密封侧压力突降相比较于突升,更易引起密封环震荡,但后者更易诱发端面接触.对于扰动引起的瞬态震荡,密封的角向行为引起震荡时间的延长与震荡幅值的减小,其与轴向行为共同决定端面接触的可能性.动静环间的极薄气膜不仅将动环的行为传递给静环,同时通过弱化轴向与角向行为的相互影响来缓解扰动所引起的密封瞬态震荡.%Transient performance under fluctuation conditions is important component of the dynamic behavior of spiral groove gas face seals,the current research for which mainly focuses on the steady-state performance.A research on the transient response to pressure-drop fluctuation is performed.The results show that the decrease of sealed pressure will cause greater oscillations in the motions while the increase of sealed pressure is easier to cause face contact.Angular motions will reduce the oscillation amplitude but prolong the oscillation time.It importantly affects the occurrence of face contact together with the axial motion.The squeeze flow effect of gas film can not only transfer the motion of the rotor to the stator,but also reduce the interactive influence of the axial and angular modes to relief oscillations caused by fluctuations.