两级刷式密封的流动计算与系统参数的配置研究

Analysis on Flows of Two-stage Brush Seals and Research on Configuration of System Parameters

基于两级刷式密封的刷丝束截面二维叉排管束模型,利用计算流体动力学(CFD)方法研究两级刷式密封刷丝束截面泄漏流的压力和流速分布规律,分析级数和级间距对出口平均轴向流速的影响,以及上下游级刷丝排数对级间分压比的影响规律。结果表明:上下游级刷丝排数相同时,两级刷式密封存在级间压力不均匀性,下游级承受的压降要大于上游级承受的压降,压力增大会加剧级间压力不均匀性;两级刷式密封的泄漏量比单级的泄漏量要小,当级数大于3后泄漏量的减少量很小;增加上游级刷丝排数或者减少下游级刷丝排数能改善级间压力不均匀性。

The leakage flow fields and pressure distributions of the two-stage brush seal were investigated based on a two-dimensional closed staggered tube bundle model of the bristle pack cross section that was solved using computational fluid dynamics （CFD） .The effect of number of stages and clearances between stages on the average outlet axis velocity and the effect of pressure ratio and number of up and down stage axial bristle rows on the inter-stage imbalance of pressure drops were analyzed.The results show that inter-stage imbalance of pressure drops is existed in two stage brush seals when the number of up stage axial bristle rows equals to the down stage and pressure drops of the down stage are larger than that of the up stage, the whole pressure drops will increase the inter-stage imbalance of pressure drops.The leakage is decreased with the increasing of the number of stage and the leakage reduction tends to be slow when the stage number is greater than three.Increasing the up stage axial bristle rows and decreasing the down stage ones can improve the inter-stage imbalance of pressure drops.