刷丝磨损对刷式密封泄漏流动特性影响数值与实验研究

采用有限元分析与计算流体力学相结合的方法，建立了考虑刷丝磨损的刷式密封泄漏流动特性求解模型，设计搭建了基于柱面圆周摩擦形式的刷式密封摩擦磨损特性实验装置，实验研究了刷丝与转子间正压力特性，在实验验证数值计算准确性的基础上，研究了刷丝磨损对刷式密封泄漏流动特性的影响规律。研究结果表明:从刷丝束上游到下游，刷丝与转子间正压力和刷丝磨损长度均先减小后增大；刷丝磨损长度随干涉量、刷丝直径的增加而增大，随压比、刷丝长度的增加而减小。考虑刷丝磨损的刷式密封泄漏量随压比、干涉量、刷丝直径的增加而增大，随着刷丝长度的增加而减小。提出泄漏量变化率表征刷丝磨损对刷式密封泄漏特性的影响程度，泄漏量变化率随刷丝直径的增加而增大，随着刷丝长度和压比的增加而减小；在压比为2.5的工况下，当刷丝直径从0.09 mm增至0.11 mm时，泄漏量变化率从9.53%增至19.18%；当刷丝长度从15.556 mm增至17.556 mm时，泄漏量变化率从13.47%降至5.38%。增加刷丝长度并减小刷丝直径可以降低刷丝磨损对刷式密封封严性能的影响。 

Numerical and experimental research on influence of brush bristle wear on leakage and flow characteristics of brush seal

Using a combination of finite element analysis and computational fluid dynamics，a model for solving the leakage and flow characteristics of the brush seal considering the wear of the brush bristle was established，and an experimental device for the friction and wear characteristics of the brush seal based on the cylindrical circumferential friction was designed and built.The positive pressure characteristics between the brush bristle and the rotor were studied by experiment.Based on the experimental verification of the accuracy of the numerical simulation，the influence of the brush bristle wear on the leakage and flow characteristics of the brush seal was studied.The research results showed that from the upstream to the downstream of bristle pack，the positive pressure between the brush bristle and the rotor，and the wear length of the brush bristle both decreased first and then increased；the wear length of the brush bristle increased with the increase of the amount of interference and the diameter of the brush bristle，and decreased with the increase of pressure ratio and the length of the brush bristle.The leakage of the brush seal considering the wear of the brush bristle increased with the increase of the pressure ratio，the amount of interference and the diameter of the brush bristle，and decreased with the increase of the bristle length.The viewpoint was proposed that the change rate of leakage characterized the degree of influence of the brush bristle wear on the leakage characteristics of the brush seal.The change rate of the leakage increased with the increase of the diameter of the brush bristle，and decreased with the increase of the length of the brush bristle and the pressure ratio.Under pressure ratio of 2.5 conditions，when the diameter of the brush bristle increased from 0.09 mm to 0.11 mm，the change rate of leakage increased from 9.53% to 19.18%；when the length of the brush bristle increased from 15.556 mm to 17.556 mm，the change rate of leakage decreased from 13.47% to 5.38%.Increasing the length of the brush bristle and reducing the diameter of the brush bristle can reduce the influence of bristle wear on the sealing performance of the brush seal.