中低压干气密封螺旋槽结构参数优化

Structural parameter optimization of spiral groove dry gas seal under low or medium pressure

基于完全析因设计方法，开展中低压干气密封端面螺旋槽几何结构参数优化。基于气体润滑理论，对中低压条件下螺旋槽干气密封的动压开启力增长率、气膜刚度和刚漏比等密封特性参数进行分析，获得了中压和低压条件下螺旋槽几何结构参数的优选值范围，提出“螺旋槽干气密封特性参数优化带”。结果表明：特性参数优化带能较好地反映螺旋槽干气密封在不同压缩数下的最优性能水平；在中低压高速条件下，当螺旋角β=10°～25°，槽深hg=5～10μm时能获得较优的密封性能；当槽坝比αg=1.5～4.0，槽长宽比λ=2～8时能获得较好的动压效应和轴向气膜稳定性；当槽坝比αg=0.7～1.5，槽长宽比λ=2～5时能获得较好的综合密封性能。

Based on full factorial design, optimization of structural parameters of a spiral groove dry gas seal （S-DGS） under low or medium pressure was performed. Based on the theory of gas lubrication, the sealing characteristic parameters, such as increase ratio of hydrodynamic open force, film stiffness and film stiffness to leakage ratio of an S-DGS under low or medium pressure were analyzed, and the preferred value ranges of structural parameters of spiral grooves were obtained. The concept of characteristic parameter optimization zone of an S-DGS was presented. The optimum sealing performance with different compressibility numbers of an S-DGS could be properly reflected by characteristic parameter optimization zone. When an S-DGS was operated under low or medium pressure and at high-speed, excellent sealing performance could be obtained for an S-DGS when spiral angle was between 10° and 25° and groove depth was between 5μm and 10μm. Excellent hydrodynamic effect and axis film stability could be obtained when groove-to-dam ratio was between 1.5 and 4.0 and groove length-width ratio was between 2 to 8. Excellent comprehensive sealing performance could be obtained when groove-to-dam ratio was between 0.7 and 1.5, groove length-width ratio was between 2 to 5.