基于流固耦合的刷式密封泄漏特性理论与实验

理论与实验两方面研究了刷式密封泄漏流动特性及影响因素。建立了考虑刷丝变形的刷式密封泄漏流动特性流固耦合理论模型,实验研究了刷式密封泄漏量随进出口压比和转速等的变化规律,并与理论求解模型对比验证。在此基础上,运用理论模型分析了不同结构参数对密封泄漏量的影响规律,验证了构造的刷式密封泄漏量理论计算公式的准确性。研究结果表明:径向间隙一定时,刷式密封泄漏量随压比的增大而近似线性增加,转速对刷式密封的泄漏量影响不大;刷丝直径和刷丝间隙通过影响气体在刷丝束区域有效流通面积来影响泄漏量,有效流通面积越小,泄漏量越小;反之,则越大;随着刷丝直径、刷丝轴向排数的增大,刷式密封泄漏量逐渐降低;随着刷丝间隙的增大,泄漏量逐渐增大;随着后挡板保护高度、刷丝与后挡板轴向间隙的增大,泄漏量先显著增大后缓慢增加,最后趋于稳定;所构造的泄漏量理论公式可以准确预测刷式密封的泄漏量,为刷式密封结构优化设计提供理论依据。 

Theory and experiment on the leakage characteristics of brush seals based on fluid-structure interaction

The leakage flow characteristics and the influencing factors of the brush seals were studied both theoretically and experimentally. A fluid-structure interaction theoretical model was established to analyze the leakage flow characteristics of brush seals. Experiments were presented to test the leakage quantity of brush seals with different pressure ratios and rotational speeds and compared with the theory solution model to verify. Based on the accuracy of the theory computational model, the effect law of the brush seal leakage quantity in different structural parameters was analyzed, and the formula for predicting the leakage quantity of brush seals was constructed. The results showed that, the leakage quantity of the brush seals increased approximately linearly with the increase of the pressure ratio when the radial clearance was fixed. The rotational speed had little influence on the leakage quantity of the brush seals. Bristles diameter and the clearance of the bristles affected the leakage quantity through affecting the effective flow area of the gas in the brush area, the smaller effective flow area led to the smaller leakage quantity. With the increase of the bristles diameter and the axial rows of the bristles, the leakage quantity of the brush seals decreased gradually. The leakage quantity increased with the increase of the bristles clearances. As the backing plate fence height and the axial clearance between the last row bristles and the backing plate fence increased, the leakage quantity firstly increased rapidly, and finally became stable. The constructed theoretical formula of leakage quantity can accurately predict the leakage quantity of brush seals and provide a theoretical basis for the optimization design of brush seals structure.