Influence of steam parameters on static and dynamic characteristics of labyrinth seal
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摘要:
目的 为了研究工质参数对透平机械中密封动静特性的影响, 方法 建立梳齿密封三维数值模型,分别以空气和水蒸汽为工质,应用计算流体力学(CFD)方法和旋转坐标系方法分析不同水蒸汽参数对密封泄漏性能和动力特性系数的影响。 结果 结果表明:工质为空气和水蒸汽时,密封的泄漏特性区别很大,其流体激振力与涡动速度分别呈线性和二次非线性的变化关系。当水蒸汽温度增加时,密封动力特性系数的变化将导致系统的稳定性下降。 结论 因此工质参数对透平机械的系统稳定性具有重要意义,在实际应用中需要考虑工质参数对密封动静特性及转子系统的影响。 Abstract:Objectives In order to study the influence of working medium parameters on the static and dynamic characteristics of seals in turbomachinery, Methods a three-dimensional model of a labyrinth seal was created, and air and steam were applied in the numerical simulation. The Computational Fluid Dynamics (CFD) method and a rotating frame were applied to analyze the influence of different steam parameters on the leakage characteristics and dynamic characteristic coefficients. Results The results show that great differences in leakage flow rate are apparent under different air and steam conditions, and the fluid-induced force shows linear and nonlinear variation with the increasing whirl speed. When the steam temperature increases, the system stability decreases as the dynamic characteristic coefficients change. Conclusions In consequence, working medium parameters are of great significance for turbine stability, and the influence of working medium parameters on the static and dynamic characteristics of seals should be given great attention in practical application. -
表 1 CFD仿真模型的参数
Table 1. Parameters of CFD simulation model
参数 仿真值 转子转速/(r·min-1) 11 097 入口压力/MPa 3.447 入口温度T/K 366.7, 523, 549, 575, 601 出口压力/MPa 1.724 工质 空气(理想气体)、水蒸汽 表 2 密封泄漏量对比
Table 2. Comparison of seal leakage flowrate
工质 文献[19]仿真值 本文仿真值 空气 1.08 1.094 水蒸汽 - 6.54 表 3 动力特性系数对比
Table 3. Comparison of dynamic characteristic coefficients
动力特性系数 文献[19]仿真值 本文仿真值 空气 空气 水蒸汽 K /(N·m-1) 1.88×106 4.59×106 3.55×106 k /(N·m-1) -7.20×105 -8.19×105 -3.93×105 C /(N·s·m-1) 1.6×103 1.56×103 1.39×104 c /(N·s·m-1) 1.24×103 1.27×103 1.97×104 M / kg - -0.438 15.78 m / kg - -0.653 -11.89 表 4 不同水蒸汽温度的密封泄漏特性
Table 4. Seal leakage characteristics under different steam temperatures
温度T/K 泄漏量/(kg·s-1) 比容/(m3·kg-1) 运动粘度/(m2·s-1) 366.7 6.54 1.037×10-3 3.137×10-7 418 6.52 1.083×10-3 2.058×10-7 444 6.49 1.114×10-3 1.773×10-7 470 6.43 1.150×10-3 1.575×10-7 496 6.36 1.194×10-3 1.434×10-7 523 6.23 5.985 9×10-2 1.052 9×10-6 549 6.11 6.519×10-2 1.227×10-6 575 5.89 6.998 2×10-2 1.401 2×10-6 601 5.44 7.445 6×10-2 1.578 5×10-6 -
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