转子轴向位移对迷宫密封泄漏特性的影响

Effects of Rotor Axial Displacement on Leakage Flow Characteristics of Labyrinth Seal

采用数值求解三维雷诺平均的N-S方程的方法,研究了透平机械的转子轴位移、汽封密封压比对典型迷宫密封泄漏特性的影响规律。在定转速、定密封间隙情况下计算典型迷宫密封在6种密封压比、4种轴向位移距离下的泄漏特性。研究结果表明:在所分析的工况下,转子轴向位移对泄漏量具有较大影响;位移距离小于1mm时,泄漏量随位移的增大而增大;位移距离大于1mm时,泄漏量随位移的增大而减小。在迷宫密封泄漏量Egli计算公式的基础上,通过引入修正系数修正转子轴向位移对迷宫密封泄漏量的影响,构建了新的预测迷宫密封在转子发生位移时泄漏流量的计算公式,并进行了数值验证。研究结果可为迷宫密封轴向间隙的设置提供参考。

The effects of pressure ratio and rotor axial displacement on the leakage behavior of a typical labyrinth seal were numerically investigated. Under constant sealing gap and rotational speed flow condition, the Reynolds-Averaged Navier-Stokes （RANS） equations and standard turbulent model were utilized to obtain the leakage flow characteristics of the labyrinth seal at four displacement distances and six pressure ratios. Numerical simulation results show that rotor axial displacement significantly influences leakage of the labyrinth seal. But there exists a critical axial displacemert distance, namely, the leakage flow rate of the labyrinth seal increases with the increase of the displacement distance when the distance is less than 1 ram, however, when the displacement distance is larger than 1 ram, the leakage flow rate decreases with the increase of the displacement distance. Based on Egli formular, a computational formulation was established and verified to predict the leakage flow rate of the labyrinth seal under the condition of rotor axial displacement through introducing amending coefficient. The results can provide reference for the axial gap setting of the labyrinth seal.