迷宫密封转子动力学特性的数值模拟

采用数值求解三维Reynolds-Averaged Navier-Stokes(RANS)方程,研究了具有16个齿的迷宫密封转子动力学特性,分析了在两种转速条件下进口预旋对迷宫密封转子动力特性系数的影响,计算了无进口预旋时,在两种压比条件下,迷宫密封系统的交叉刚度和直接阻尼系数随转速的变化关系,并将计算结果与实验值和两控制容积BF(Bulk Flow)方法计算值进行了比较.研究结果表明:所采用的数值方法能较好地预测迷宫密封的转子动力特性,且计算结果优于两控制容积BF方法.对于迷宫密封,交叉刚度与进口预旋近似成正比关系,且随着转速的增大而增大;直接阻尼对转速和进口预旋均不敏感,但随压比的增大而显著增大.过大的进口预旋和转速均会使转子的稳定性降低;工作在较大转速下的迷宫密封系统可以通过施加合理的进口预旋来增强转子的稳定性.

Numerical Simulation of the Kinetic Characteristics of a Labyrinth Gland Rotor

By way of seeking numerical solutions to a three-dimensional RANS(Reynolds-Averaged-Navier-Stokes) equation,studied were the kinetic characteristics of a 16-tooth labyrinth gland rotor and analyzed was the influence of the inlet pre-swirling on the kinetic characteristic coefficient of the rotor in question at two rotating speeds.In addition,in the absence of the inlet pre-swirling and at two pressure ratios,the variation relationship of the cross rigidity and direct damping coefficient of the labyrinth gland system with the rotating speed was calculated and the calculation results were compared with the test ones and the values calculated by using two volume controlled BF(bulk flow) methods.The research results show that the numerical method adopted can predict relatively well the kinetic characteristics of the labyrinth gland rotor and the calculated results are better than those obtained by using dual volume controlled BF methods.As regards labyrinth glands,the cross rigidity is approximately in direct proportion with the inlet pre-swirling and increases with an increase of the rotating speed.The direct damping is not sensitive to both the rotating speed and inlet preswirling,but increases remarkably with an increase of the pressure ratio.An excessively large inlet pre-swirling and rotating speed can invariably reduce the stability of the rotor.The labyrinth gland system operating at a bigger rotating speed can enhance its rotor stability by applying a rational inlet pre-swirling.