刷式密封温度场数值研究

Numerical investigation of temperature field in brush seals

分析了刷式密封中摩擦生热和热传递的机理,在此基础上将刷丝区域视为各向异性多孔介质、用阻抗力表示刷丝对流体的阻碍作用、以摩擦热为热源建立了计算流体动力学(CFD)模型;得到了刷式密封区域的压力、速度以及温度场分布;并得出了密封区域最高温度和安装过盈量、密封压差的对应关系.结果表明刷丝与转子接触面上存在显著温升,温度场在径向呈阶梯状分布且温度值沿转子外法线方向衰减;密封区域流体对流和出口泄漏流对于温度分布影响较大.计算结果能为刷式密封结构设计、接触副材料选择和密封环安装方式提供参考和指导.

The mechanism of frictional heat generation and heat transfer in brush seals was analyzed and a computational fluid dynamics （CFD） model was developed. In the model,the brush was treated as an anisotropic porous region with nonlinear resistance coefficients and the frictional heat as a heat source. The pressure distribution,velocity field and temperature field were obtained and the maximum temperature under various interference and pressure difference conditions were studied. The investigation shows a steep temperature rise in bristle-rotor interface,which diminishes further away in the radial direction; fluid convection and leakage flow affect temperature distribution deeply. The results can be used to guide brush seal geometry design,contact-pair material selection and interference fit.