凹槽迷宫密封封严特性的数值研究

Numerical Investigation of Leakage Effects of Rub-grooves on Labyrinth Seal

采用计算流体动力学软件、RNG k-ε模型、Simple算法和结构化网格,研究不同间隙、压比、转速等工况下密封表面凹槽结构对凹槽迷宫密封三维流场和泄漏流动特性的影响。结果表明:凹槽迷宫密封的凹槽结构可以更加充分地耗散气体的动能,从而有效地阻滞气体流动,减小气体的泄漏;迷宫密封的泄漏量随间隙的增大而增大,但凹槽迷宫密封泄漏量和泄漏量增加率都小于普通迷宫密封;随着压比的增大,凹槽迷宫密封的泄漏量有所增加,但相比于普通迷宫密封,其泄漏量增加的趋势在逐渐减小;随着转速的增加,凹槽迷宫密封更容易在凹槽内形成气旋效应,从而使其封严性能显著提高。

The effect of the rub-groove structure of seal surface on three dimensional （3-D）flow field and leakage flow rate of the rub-groove labyrinth seal was researched by using computing hydrokinetics software,RNG k-εmodel,Simple algorithm and structural gridding under different conditions of the clearance,the pressure ratio and the rotational speeds. The results show that the groove seal structure can realize the full gas kinetic energy dissipation,thus it can block the gas flow and reduce the gas leakage effectively.The leakage flow of labyrinth seal is increased with the increase of the clear-ance,but both the amount and the rate of leakage of the rub-groove labyrinth seal are less than the common labyrinth seal. Along with the rise of pressure ratio,the leakage flow of rub-groove labyrinth is increased,but in a reducing gradient com-pared to the common labyrinth seal.Along with the increase of rotational speed,rub-groove labyrinth seal are more likely to form the effect of cyclone in the rub-groove,so that the seal performance is improved significantly.