为了计算刷式密封的介质流动, 建立了刷丝束截面的2维紧凑叉排管束模型, 并利用计算流体动力学(CFD)方法求解。研究了刷丝束截面泄漏流的压力和流速分布及压差、刷丝轴向排数和管距对泄漏特性的影响。结果表明: 基于周向1排与周向6排刷丝的模型所计算的压力和流速基本吻合, 各数据点的误差均小于3%, 所计算的压力梯度结果与转子表面压力测量结果基本吻合。0.2 MPa下, 最下游刷丝的压降和最高流速增量分别大约是上游刷丝的6倍和8倍。压差增加会加剧最下游刷丝间隙处的压降和流速增量。出口平均轴向流速随着压差的增大而呈线性增长, 随着刷丝轴向排数的增大而呈自然对数下降。减小刷丝管距可以在常见的压差和刷丝排数范围内显著提高密封效果。
Abstract
The flows in brush seals were modeled using a two-dimensional closed staggered tube bundle model of the bristle pack cross section that was solved using computational fluid dynamics (CFD). The pressure and velocity distributions of the leakage were studied for various pressure differentials, number of axial bristle rows, and inter-tube spacing. The results show that the calculated pressures and velocities with 1 and 6 bristles in the circumferential direction are very similar with differences less than 3% for each data point and the calculated pressure gradients agree with rotor surface pressure measurements. For an inlet pressure of 0.2 MPa, the pressure drop across the last downstream bristle is about 6 times that over the upstream bristles while the maximum velocity rise is about 8 times greater. The growing pressure differential exacerbates the pressure drop and the maximum velocity rise across the last downstream bristle. The average outlet axis velocity increases linearly with the increasing pressure differentials and deceases logarithmically with the number of axial bristle rows. The sealing effect can be significantly enhanced by reducing the inter-tube spacing of the bristles for normal pressure differentials and number of axial bristle rows.
关键词
刷式密封 /
泄漏 /
叉排管束 /
计算流体力学
Key words
brush seal /
leakage /
staggered tube bundle /
computational fluid dynamics (CFD)
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基金
国家自然科学基金资助项目(51305224)
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