刷式密封泄漏流动特性流固耦合研究

Study on the leakage flow characteristics of brush seals based on fluid-structure interaction

刷式密封是旋转机械的关键部件,由其引起的泄漏损失直接影响旋转机械的工作效率。分析了刷式密封的流固耦合特性,应用双向流固耦合与动网格技术,建立刷式密封瞬态三维流固耦合求解模型。在实验验证流固耦合求解模型准确性的基础上,分析刷式密封的泄漏流动特性,研究刷式密封几何参数等因素对其泄漏特性的影响规律。研究结果表明,刷式密封泄漏量随着后挡板保护高度的增大而增加;随着刷丝束与后挡板之间轴向间隙的增大,泄漏量先增大,然后趋于稳定不变;随着刷丝排数的增加,泄漏量先迅速下降,然后下降速度趋缓。研究结果为刷式密封结构设计提供理论依据。

Brush seals are the key parts of rotating machines,because leakage loss caused by brush seals affect the work efficiency of the machine. In this paper,the leakage flowcharacteristics of brush seals were analyzed using the theory of fluid-structure interaction. A three-dimensional computational model was presented based on two-way fluid-structure interaction,and moving grids technique and its validation was tested by experiment. The flowfield characteristics were further analyzed and the effects of some factors（ e. g. geometric parameters） on the leakage characteristics were also investigated. Numerical results showthat the leakage rate increases with the increase of backing plate fence height. The leakage rate increases with increasing the axial clearance between the brush bristle and back plate,and then tends to be stable. As the bristle rownumber increases,the leakage rate first decreases rapidly,then slowly,and finally tends to a value. The results of this study can provide fundamental support for designing brush seals.