基于多孔介质模型的刷式密封泄漏流动特性研究

采用数值求解基于多孔介质模型的Reynolds-averaged Navier-Stokes方程技术，对刷式密封内泄漏流动特性进行了详细的数值研究．根据刷式密封的泄漏量试验数据，确定了刷丝束多孔介质的渗透率系数．利用所确定的渗透率系数，数值计算和分析了7种压比和5种径向间隙条件下的某轴端刷式密封的泄漏量和泄漏流动形态，并且与迷宫式密封进行了比较．结果表明：在相同的压比下，刷式密封的泄漏量小于迷宫式密封；压比影响刷式密封的泄漏量，但对泄漏流动形态的影响可以忽略；径向间隙不仅影响刷式密封的泄漏量，而且影响泄漏流动形态；在相同的径向间隙下，压比越大则泄漏量越大；在相同的压比条件下，径向间隙越小则泄漏量越小．研究工作可对刷式密封在汽轮机中的应用提供理论依据和技术参考．

Study on the Leakage Flow Characteristics of Brush Seal Based on Porous Medium Model

The leakage flow behavior through a brush seal was numerically investigated using the Reynolds-averaged Navier-Stokes solution based on the porous medium model. The permeability coefficients of the bristle pack were determined according to the published experimental data. The leakage flow rate and flow characteristics of a typical shaft brush seal were studied at seven pressure ratios and five kinds of the sealing clearances using the permeability coefficients obtained. The numerical results show that the leakage flow rate of the brush seal is smaller than that of the labyrinth seal at the same pressure ratio. Moreover, the pressure ratio can affect the leakage flow rate while its influence on the leakage flow pattern can be neglected. In addition, the leakage flow rate increases linearly with the increase of the pressure ratio at a fixed sealing clearance for the brush seal. The leakage flow rate of the brush seal decreases with the decrease of sealing clearance at a fixed pressure ratio.