﻿ 柔片式密封数值计算及性能分析
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Numerical simulation and performance analysis of leaf seal
LIU Jian, WANG Zhili , DING Lei
School of Mechanical Engineering and Automation, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
Abstract:In order to obtain the result of pressure and velocity distribution and leakage of the leaf seal system which is applied to high-speed rotor, a mathematical model of sealing zone flow field calculated numerically with SIMPLER method and finite difference method was established. A software based on the algorithm referred was also designed specially for the performance analysis of leaf seal system. The influence of different structure parameters and working conditions on the system's performance was discussed. Analysis result shows that the leakage increases linearly with the sealing pressure and decreases slightly with the increase of rotor speed. Increasing width, reducing spacing between front/back cover plate to rotor and decreasing length are beneficial in decreasing the leakage of the system. While changing installation angle direction of the leaf has little influence on leakage. Research on dynamic response between leaf and rotor will be carried out based on the results of the flow field.
Key words: leaf seal     SIMPLER algorithm     Reynolds equation     flow field     performance analysis

1 柔片式密封结构及其设计参数

 图 1 柔片式密封结构Fig. 1 Structure of leaf seal

D—转子直径;Fr,Br—前/背板-转子间的距离;Fl,Bl—前/背板-柔片间的距离;l—柔片长度;w—柔片宽度;d—柔片厚度;c1,c2—两柔片间最小/大距离;c3,c4—柔片末端距转子最小/大距离;α—柔片安装角度;pin,pout—入口、出口压力.

 图 2 柔片式密封基本设计参数Fig. 2 Basic design parameters of leaf seal
2 数学模型

2.1 流场计算区域

2.2 基本方程

2.3 数值计算方法

 图 3 交错网格Fig. 3 Staggered grid

 图 4 交界处流体的流动Fig. 4 Fluid flow at border

 图 5 交界处网格Fig. 5 Grid at border

 图 6 流场求解流程图Fig. 6 Flow chart of solution to flow field
2.4 边界条件

3 计算结果与分析

 图 7 程序界面Fig. 7 Interface of procedure
3.1 计算参数的取值

3.2 压力场和速度场

3.3 性能分析 3.3.1 密封压差对泄漏量的影响

3.3.2 转子转速对泄漏量的影响

 图 8 计算区域压力场分布Fig. 8 Distribution of pressure field of calculated region

 图 9 计算区域速度场分布Fig. 9 Distribution of velocity field of calculated region

 图 10 ANSYS仿真压力场分布Fig. 10 Distribution of pressure field by ANSYS simulation

 图 11 密封压差对泄漏量的影响Fig. 11 Effect of different sealing differential pressures on leakage

 图 12 转子转速对泄漏量的影响Fig. 12 Effect of different rotor rotation speeds on leakage
3.3.3 柔片结构对泄漏量的影响

 图 13 柔片尺寸对泄漏量的影响Fig. 13 Effect of different leaf sizes on leakage
3.3.4 前/背板-转子间距对泄漏量的影响

 图 14 前/背板-转子间距对泄漏量的影响 (Δp=0.3MPa)Fig. 14 Effect of different Fr/Br on leakage (Δp=0.3MPa)
3.3.5 柔片安装角度对泄漏量的影响

 图 15 柔片安装角度对泄漏量的影响Fig. 15 Effect of different leaf installation angles on leakage
4 结 论

1) 分区域求解的柔片式密封计算模型计算结果合理,构建的程序计算速度快、稳定性好,能够较好地用于柔片式密封性能分析.

2) 分析表明密封系统的泄漏量随密封压差的增大近似呈线性趋势增加,随转子转速的增加略有降低;增加柔片宽度,减小柔片长度、前/背板-转子间距均有利于降低密封系统的泄漏量,在结构设计时应予考虑.

3) 本文分析了柔片式密封系统的稳态流场,柔片的变形、摩擦热等因素在流场分析中的作用和响应有待进一步分析研究,如:摩擦热对流场及密封面接触力变化的影响、柔片变形及其振动特性、密封压力脉动对转子的影响等.

 [1] 胡广阳. 航空发动机密封技术应用研究[J].航空发动机,2012,38(3):1-4. Hu G Y.Application research of seal technologies for aeroengine[J].Aeroengine,2012,38(3):1-4(in Chinese). Cited By in Cnki (9) [2] Aksit M F A. Computational study of brush seal contact loads with friction[D].New York:Rensselaer Polytechnic Institute, 1998. Click to display the text [3] 谢晓俊,康宁. 低泄漏高寿命刷式封严的数值计算[J].航空动力学报,2003,18(6):824-826. Xie X J,Kang N.Numerical of low and high endurance brush seal[J].Journal of Aerospace Power,2003,18(6):824-826(in Chinese). Cited By in Cnki (4) [4] 王之栎,梁小峰, 黄其武.刷式密封二维模型数值计算[J].航空动力学报,2008,23(8):1461-1465. Wand Z L,Liang X F,Huang Q W.Two-dimensional model mathematical simulation of brush seals[J].Journal of Aerospace Power,2008,23(8):1461-1465(in Chinese). Cited By in Cnki (3) [5] Jahn I H J, Franceschini G,Owen A K,et al.Experimental characterisation of the stiffness and leakage of a prototype leaf seal for turbine applications,ASME Paper GT2008-51206[R].Berlin:ASME,2008. Click to display the text [6] Jahn I H J, Gillespie D,Cooper P.Hydrodynamic air-riding in leaf seals,ASME Paper GT2013-95585[R].Berlin:ASME, 2013. Click to display the text [7] Flower R F J. Abdichtung:European,Patent EP0391676A1[P].1990-10-10. [8] Wright C. Resilient strip seal arrangement:United States,Patent US0006267381B1[P].2001-07-31. [9] Nakane H, Maekawa A,Akita E,et al.The development of high performance leaf seals,ASME Paper GT2002-30243[R].Berlin:ASME,2002. [10] Grondahl C M, Dudley J C.Film riding leaf seals for improved shaft sealing,ASME Paper GT2010-23629[R].Berlin:ASME, 2010. [11] Jahn I H J, Owen A K,Gillespie D.Negative stiffness in gas turbine leaf seals,ASME Paper GT2011-46483[R].Berlin:ASME, 2011. [12] 梁亚坤,王之栎, 王伟.柔片式密封泄漏量流动的数值仿真分析[J].航空动力学报,2013,28(9):1975-1979. Liang Y K,Wang Z L,Wang W.Numerical simulation and analysis of leaf leakage flow[J].Journal of Aerospace Power,2013,28(9):1975-1979(in Chinese). Cited By in Cnki [13] 王福军. 计算流体动力学分析——CFD软件的原理与应用[M].北京:清华大学出版社,2004:10-11. Wang F J.Computational fluid dynamics analysis:Principle and application of CFD software[M].Beijing:Tsinghua University Press,2004:10-11(in Chinese). [14] 沈心敏,闻英梅, 孙希桐,等.摩擦学基础[M].北京:北京航空航天大学出版社,1988:57-59. Shen X M,Wen Y M,Sun X T,et al.Tribology foundation[M].Beijing:Beihang University Press,1988:57-59(in Chinese). [15] Patankar S V. 传热与流体流动的数值模拟[M].张政,译.北京:科学出版社,1984:130-157. Patankar S V.Numerical heat transfer and fluid flow[M].Translated by Zhang Z.Beijing:Science Press,1984:130-157(in Chinese). [16] 徐广州,马纲, 沈心敏.气体雷诺方程数值方法比较和压场的讨论[C]//2006全国摩擦学学术会议——纪念摩擦学40周年会议论文集.哈尔滨:中国机械工程学会摩擦学分会,2006:128-130. Xu G Z,Ma G,Shen X M.Comparison of numerical method for gas Reynolds equation and discussion of pressure field[C]//Proceedings of Symposium on Tribology in 2006:40th Anniversary of Tribology.Harbin:Tribology Institute of Chinese Mechanical Engineering Society,2006:128-130(in Chinese). Cited By in Cnki (0)

#### 文章信息

LIU Jian, WANG Zhili, DING Lei

Numerical simulation and performance analysis of leaf seal

Journal of Beijing University of Aeronautics and Astronsutics, 2015, 41(8): 1546-1552.
http://dx.doi.org/10.13700/j.bh.1001-5965.2014.0593