Numerical analysis on performance of hydrodynamic-hydrostatic hybrid mechanical seals for turbopumps
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摘要:
针对密封端面液氧的低动力黏度难以成膜的特性,提出一种动静压结合型机械端面密封。考虑节流孔的静压效应和液膜空化效应,建立了液膜的有限元分析模型,研究了动静压型机械密封的工作原理,分析了端面动静压结构几何参数对密封性能的影响规律。研究结果表明:动静压型机械密封的节流孔将静压效应引入密封端面,螺旋槽在提高液膜动压效应基础上将经节流孔流入的介质泵送回密封腔,提高了上游泵送量。在研究范围内,推荐的动静压结构几何参数的优选范围如下:螺旋槽槽台宽比为0.6~0.7、槽坝比为0.6~0.7、槽深为12~15 μm、螺旋角为15°~18°,静压节流孔孔径为0.4~0.5 mm、节流孔个数为6~12 个。
Abstract:In view of the characteristics of low dynamic viscosity and hard film forming of liquid oxygen on the sealing face, a hydrodynamic-hydrostatic hybrid mechanical seal was proposed. Considering the hydrostatic effect of the orifice and the cavitation effect of the liquid film, the finite element analysis model of the liquid film was established to study the working principle of the hydrodynamic-hydrostatic hybrid mechanical seal and analyze the influences of the geometrical parameters of the hydrodynamic and hydrostatic structure on the sealing performance. Within the research scope, the optimum range of the geometrical parameters of the spiral groove and hydrostatic structure was as follows: the groove-weir ratio was 0.6—0.7, the groove-dam ratio was 0.6—0.7, the groove depth was 12—15 μm, the spiral angle was 15°—18°, the orifice diameter was 0.4—0.5 mm, and the orifice number was 6—12.
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表 1 几何参数与工况参数
Table 1. Geometrical parameters and operating parameters
参数 数值 参数 数值 端面外径 ro/mm 55.5 螺旋槽槽数Ng 15 端面内径 ri/mm 45.5 节流孔孔径dk/mm 0.5 螺旋槽槽台宽比β1 0.5 均压槽槽宽wj/mm 1.5 螺旋槽槽坝比β2 0.7 均压槽槽深hj/μm 200 螺旋槽槽底半径比β3 0.4 节流孔孔数m 15 螺旋角α/(°) 15 转速 n/104 (r/min) 2 螺旋槽槽深hg/μm 5 外径侧压力po/MPa 0.5 密封间隙hc/μm 5 内径侧压力pi/MPa 0.1 -
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