Numerical investigation on bristles buoyancy effect of suppressed-disturbance brush seals with fluid-structure interaction
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摘要:
提出抑扰型刷式密封结构,基于arbitrary Lagrange-Eulerian(ALE)流固耦合方法建立抑扰型刷式密封刷丝浮升效应三维瞬态求解模型,研究不同抑扰孔结构刷式密封泄漏特性和速度特性,以及抑扰孔结构参数对刷式密封刷丝浮升效应的影响规律。研究结果表明:在传统刷式密封前挡板设置抑扰孔可改变前排刷丝受力状态,前排刷丝受到与扰动方向相反的力矩,有效抑制刷丝浮升效应产生,显著提升传统刷式密封封严性能。相较于易产生刷丝浮升效应的传统刷式密封,降低抑扰孔高度、增加抑扰孔直径和排数,均可有效降低刷式密封泄漏量,其中增加抑扰孔排数至3排可降低30.2%泄漏量。设置抑扰孔结构可抑制刷丝浮升效应引起的前排刷丝形变,相比于传统刷式密封,抑扰孔高度设置为3.75 mm、抑扰孔直径设置为1.5 mm与抑扰孔排数设置为3排,分别使刷丝自由端平均变形量减少53.2%、34.8%和54.0%。
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关键词:
- 抑扰型刷式密封 /
- 刷丝浮升效应 /
- arbitrary Lagrange-Eulerian方法 /
- 流固耦合 /
- 数值分析
Abstract:Suppressed-disturbance (SD) brush seal structure was presented. A three-dimensional transient solution model for bristles buoyancy effect of the brush seal with disturbance suppression was established based on arbitrary Lagrange-Eulerian (ALE) fluid-structure coupling method. The leakage characteristics and velocity characteristics of the brush seal with different SD hole structures were studied, and the influence of the structural parameters of SD holes on bristles buoyancy effect of brush seal was studied. The results showed that the SD hole in the front plate of the traditional brush seal can change the stress state of the front bristles, and the front bristles were subjected to a torque opposite to the direction of disturbance, effectively inhibiting the bristles buoyancy effect, and significantly improving the sealing performance of the traditional brush seal. Compared with the traditional brush seal prone to produce the bristles buoyancy effect, reducing the height of the SD hole and increasing the diameter and number of the SD hole can effectively reduce the leakage of the brush seal. Increasing the number of rows of SD hole to 3 rows can reduce the leakage of brush seal by 30.2%. The setting of the SD hole structure can inhibit the deformation of the front bristles caused by the bristles buoyancy effect. Compared with the traditional brush seal, the height of the SD hole was set to 3.75 mm, the diameter of the SD hole was set to 1.5 mm, and the number of rows of the SD hole was set to 3 rows, which reduced the average deformation of the free end of the brush by 53.2 %, 34.8 % and 54.0 %.
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表 1 抑扰型刷式密封结构参数
Table 1. Structural parameters of SD brush seals
mm 参数 数值 前挡板宽度wf 1.0 后挡板宽度wb 2.0 刷丝束轴向厚度ws 1.5 前挡板保护高度hf 1.5 后挡板保护高度hb 1.0 刷丝束与转子面间隙hg 0 刷丝束与前挡板间隙wg 0.8 刷丝直径D 0.07 刷丝排列间距d 0.007 刷丝径向长度L 10.4 抑扰孔直径Ds 0.5,1.0,1.5 抑扰孔高度hs 3.75,5.95,8.15 抑扰孔周向间距δ Ds/2 表 2 网格无关性验证
Table 2. Grid independence verification
网格数量/万 泄漏量相对误差/% 82 16.43 134 9.26 193 4.14 243 0.42 -
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