Study on end face deflection of shrink-fit mechanical seals for turbo pump considering thermal-mechanical coupling effect

doi:10.11949/0438-1157.20241316

Abstract

Abstract:

Taking the shrift-fit mechanical seals used in the turbo-pumps of liquid rocket engines as the research objective, taking the interference fit effect of the stationary seal ring as well as the contact between the seal ring and its seats into consideration, the thermoelastic-hydrodynamic lubrication coupling model under cryogenic conditions is established. The interior point optimizer method for nonlinear programming (IPOPT) was employed to address the problem of deformation solution arising from the boundary contact. Subsequently, the influences of the interference fit values of the stationary seal ring, rotational speeds, and sealing pressures on the end-face deformation and thermo-elasto-hydrodynamic lubrication characteristics of the shrift-fit mechanical seals of the turbo pump under the cryogenic environment were investigated. The results show that: under the thermal coupling of the sealing ring and the contact between the sealing components, a non-monotonic film thickness distribution is generated between the end faces of the dynamic and static sealing rings along the radial direction, and the temperature deformation in the cryogenic environment is much greater than the force deformation of the sealing pressure. Moreover, the initial interference fit value of the stationary seal ring exerts an impact on the liquid film thickness distribution of the seal in the working state after grinding and removal after the assembly process. Consequently, both the interference fit value of the stationary seal ring and the thermal deformation under the cryogenic environment are crucial factors to be considered in the structural design of the seal rings. The present thermos-mechanical coupling model, considering the contact effect of the sealing components, can provide theoretical foundation for the structural optimization of the shrift-fit mechanical seal ring.

Key words: turbo pump, shrink-fit mechanical seal, cryogenic condition, primal-dual interior point optimization

摘要：

以液体火箭发动机涡轮泵用镶装式机械密封为研究对象，考虑密封静环的过盈配合作用及密封环与环座之间的接触，建立了其深冷工况下的热弹流润滑耦合模型，采用原始对偶内点优化方法（IPOPT）处理接触带来的变形求解问题，研究了静环镶装过盈量、转速和密封压力对深冷环境下涡轮泵镶装式机械密封端面变形行为及密封界面的热弹流润滑特性。结果表明，在密封环热力耦合作用及密封组件间的接触作用下，密封动静环端面间产生沿半径方向非单调变化的膜厚分布，深冷环境下的温度变形远大于密封压力的力变形；密封静环的初始过盈量在装配后的研磨去除影响工作状态下密封的液膜厚度分布，静环过盈量和深冷环境下的收缩变形是密封环结构设计中需重点考虑的因素。建立的考虑密封组件接触作用的流固热力耦合模型可为镶装式机械密封环的结构优化提供理论基础。

关键词: 涡轮泵, 镶装式机械密封, 深冷环境, 原始对偶内点优化

CLC Number:

TH 117.2

Jiatong YU, Xiangkai MENG, Wenjing ZHAO, Lei LIU, Lihao ZHANG, Xudong PENG. Study on end face deflection of shrink-fit mechanical seals for turbo pump considering thermal-mechanical coupling effect[J]. CIESC Journal, 2025, 76(6): 2900-2912.

余嘉桐, 孟祥铠, 赵文静, 刘磊, 张力豪, 彭旭东. 热力耦合作用下涡轮泵用镶装式机械密封端面变形规律研究[J]. 化工学报, 2025, 76(6): 2900-2912.

Figures/Tables 18

Fig.1 Schematics of mechanical face seal

Fig.2 Seal ring components contact pair

Fig.3 Thermal and mechanical boundary conditions of mechanical seal

Fig.4 Axial displacement of sealed static ring

Table 1 Axial displacements of end face

r/mm	轴向位移/mm		误差/%
r/mm	ANSYS结果	本文结果	误差/%
30	-17.367	-17.404	0.22
32	-13.816	-13.861	0.33
34	-10.398	-10.446	0.47
36	-7.032	-7.085	0.75
38	-3.61	-3.659	1.33
40	0.0163	0.0161	1.62
42	4.176	4.116	1.45
44	9.575	9.455	1.26

Fig.5 Computational procedure[18, 25]

Table 2 Physical parameters of seal rings［28-29］

参数	Inconel 718(-190℃)	静环石墨环
弹性模量E/GPa	212	27.7
泊松比	0.31	0.25
热膨胀系数α/(m·℃^-1)	12.63×10^-6	5.27×10^-6
热导率k/(W/(m·℃))	7.94	115

Table 3 Geometric parameters of seal face

参数	数值	参数	数值
螺旋槽根径r_g/mm	36	槽深h_g/μm	5
螺旋角γ/(°)	12	槽数N_g	12
端面外径r_o/mm	45	端面外径r_i/mm	30
螺旋槽周向开槽比α_g	0.5	螺旋槽径向开槽比α_w	0.5

Fig.6 Seal ring deflection, temperature and liquid film pressure distribution

Fig.7 Thermal and mechanical deflection of seal rings

Fig.8 Film pressure, thickness and temperature distribution

Fig.9 Axial deflection of seal ring end face at different interferences

Fig.10 Film thickness, temperature and pressure distribution at different interferences

Table 4 Leakage rate for different amounts of interference

镶装过盈量/mm	泄漏率/(ml $∙$ h^-1)
0.18	4991.56
0.19	5486.42
0.20	6195.83
0.21	6596.20
0.22	7213.79

Table 4 Leakage rate for different amounts of interference

镶装过盈量/mm	泄漏率/(ml $∙$ h^-1)
0.18	4991.56
0.19	5486.42
0.20	6195.83
0.21	6596.20
0.22	7213.79

Fig.11 Axial deflection of seal rings end face at different rotational speeds

Fig.12 Film thickness, temperature and pressure distribution at different rotational speeds

Fig.13 Axial deflection of seal ring end faces at different sealing pressures

Fig.14 Film thickness, temperature and pressure distribution at different sealing pressures

References 30

[1]	陈杰, 张秋翔, 吴露, 等. 镶装式密封环镶装质量的影响因素分析[C]//第五届全国流体密封学术会议论文集. 西安, 2011.
	Chen J, Zhang Q X, Wu L, et al. Analysis of influencing factors of mounting quality of mounting seal ring[C]//Proceedings of the 5th National Conference on Fluid Sealing. Xi'an, 2011.
[2]	张明奎. 机械密封动(静)环热套过盈量的计算[J]. 流体机械, 1994, 22(4): 47-50.
	Zhang M K. Calculation of interference of thermal sleeve of dynamic (static) ring of mechanical seal[J]. Fluid Machinery, 1994, 22(4): 47-50.
[3]	张勇, 蔺继英. 机械密封动、静环镶装变形的分析及其改进措施[J]. 流体机械, 1997, 25(4): 36-38.
	Zhang Y, Lin J Y. Analysis and improvement measures of deformation of dynamic and static rings of mechanical seals[J]. Fluid Machinery, 1997, 25(4): 36-38.
[4]	Parsons B, Wilson E A. A method for determining the surface contact stresses resulting from interference fits[J]. Journal of Engineering for Industry, 1970, 92(1): 208-218.
[5]	Zhang Y, McClain B, Fang X D. Design of interference fits via finite element method[J]. International Journal of Mechanical Sciences, 2000, 42(9): 1835-1850.
[6]	李婕. 镶装密封环密封特性的研究[D]. 北京: 北京化工大学, 2009.
	Li J. Sealing characteristiscs research of mounted sealing ring[D]. Beijing: Bejing University of Chemical Technology, 2009.
[7]	张杰, 李鲲, 吴兆山, 等. 镶装式石墨密封环的压力变形研究[J]. 润滑与密封, 2012, 37(3): 53-58.
	Zhang J, Li K, Wu Z S, et al. Study on pressure deformation of mounted carbon seal ring[J]. Lubrication Engineering, 2012, 37(3): 53-58.
[8]	王悦昶, 刘莹, 黄伟峰, 等. 过盈配合连接对核主泵机械密封性能影响的ANSYS分析[J]. 机械工程学报, 2017, 53(5): 153-159.
	Wang Y C, Liu Y, Huang W F, et al. ANSYS interference fit analysis of mechanical seals in reactor coolant pumps[J]. Journal of Mechanical Engineering, 2017, 53(5): 153-159.
[9]	刘杰. 核主泵用镶嵌式直线深槽流体动压型机械密封性能研究[D]. 杭州: 浙江工业大学, 2013.
	Liu J. Study on performance of embedded linear deep groove hydrodynamic mechanical seal for nuclear main pump[D]. Hangzhou: Zhejiang University of Technology, 2013.
[10]	李彦启, 刘启东, 刘合荣, 等. 基于热力耦合的镶嵌式机械密封端面变形分析[J]. 润滑与密封, 2021, 46(9): 113-119.
	Li Y Q, Liu Q D, Liu H R, et al. Analysis of face deformation of mosaic type mechanical seals based on thermal-mechanical coupling[J]. Lubrication Engineering, 2021, 46(9): 113-119.
[11]	李鲲, 姚黎明, 吴兆山, 等. 机械密封环端面变形研究[J]. 润滑与密封, 2001, 26(5): 44-47.
	Li K, Yao L M, Wu Z S, et al. Study on face deformation of mechanical seal[J]. Lubrication Engineering, 2001, 26(5): 44-47.
[12]	彭旭东, 冯向忠, 胡丹梅, 等. 非接触式气体润滑密封变形的数值分析[J]. 摩擦学学报, 2004, 24(6): 536-540.
	Peng X D, Feng X Z, Hu D M, et al. Numerical analysis of deformation of a non-contacting gas lubricated seal[J]. Tribology, 2004, 24(6): 536-540.
[13]	王金红, 陈志, 刘凡, 等. 密封环支撑边界条件对机械密封端面变形的影响[J]. 化工学报, 2020, 71(4): 1744-1753.
	Wang J H, Chen Z, Liu F, et al. Influence of support boundary conditions of a seal ring on deformation of mechanical seal end face[J]. CIESC Journal, 2020, 71(4): 1744-1753.
[14]	康玉茹, 孟祥铠, 彭旭东, 等. 核主泵用流体静压型机械密封耦合模型与性能分析[J]. 流体机械, 2011, 39(11): 22-27.
	Kang Y R, Meng X K, Peng X D, et al. Coupling model and performance analysis of hydrostatic mechanical seals for reactor coolant pumps[J]. Fluid Machinery, 2011, 39(11): 22-27.
[15]	He Q, Huang W F, Liu Y, et al. Contact status between seal ring and its support: crucial factor in hydrostatic mechanical face seal[J]. Industrial Lubrication and Tribology, 2019, 71(7): 885-892.
[16]	Metcalfe R. End-face seal deflection effects—the problems of two-component stationary or rotating assemblies[J]. ASLE Transactions, 1980, 23(4): 393-400.
[17]	Galenne E, Pierre-Danos I. Thermo-elasto-hydro-dynamic modeling of hydrostatic seals in reactor coolant pumps[J]. Tribology Transactions, 2007, 50(4): 466-476.
[18]	彭旭东, 康玉茹, 孟祥铠, 等. 核主泵用流体静压型机械密封性能的影响因素研究[J]. 机械工程学报, 2012, 48(17): 83-90.
	Peng X D, Kang Y R, Meng X K, et al. Study on factors affecting seal performance of a hydrostatic mechanical seal in reactor coolant pumps[J]. Journal of Mechanical Engineering, 2012, 48(17): 83-90.
[19]	高斌超, 孟祥铠, 李纪云, 等. 机械密封热力耦合有限元模型与密封性能分析[J]. 摩擦学学报, 2015, 35(5): 550-556.
	Gao B C, Meng X K, Li J Y, et al. Thermal-mechanical coupled finite element model and seal performance analysis of mechanical seals[J]. Tribology, 2015, 35(5): 550-556.
[20]	Kou G Y, Li X H, Wang Y, et al. Multifield coupling model and performance analysis of a hydrostatic mechanical seal[J]. Energies, 2020, 13(19): 5159.
[21]	李振涛, 郝木明, 杨文静, 等. 螺旋槽液膜密封端面空化发生机理[J]. 化工学报, 2016, 67(11): 4750-4761.
	Li Z T, Hao M M, Yang W J, et al. Cavitation mechanism of spiral groove liquid film seals[J]. CIESC Journal, 2016, 67(11): 4750-4761.
[22]	周绍玉. 核主泵用流线槽机械密封热流固耦合分析[D]. 成都: 西华大学, 2022.
	Zhou S Y. Thermal-fluid-solid coupling analysis of mechanical seal of groove for nuclear main pump[D]. Chengdu: Xihua University, 2022.
[23]	Forsgren A, Gill P E, Wright M H. Interior methods for nonlinear optimization[J]. SIAM Review, 2002, 44(4): 525-597.
[24]	谢玉汉, 孟祥铠, 赵文静, 等. 高压工况上游泵送机械密封热力变形与密封性能分析[J]. 化工学报, 2023, 74(10): 4241-4251.
	Xie Y H, Meng X K, Zhao W J, et al. Thermal mechanical deformation and sealing performance analysis of upstream pumping mechanical seals under high-pressure conditions[J]. CIESC Journal, 2023, 74(10): 4241-4251.
[25]	郭嵩. 接触式机械密封热力耦合模型及密封性能分析[D]. 杭州: 浙江工业大学, 2021.
	Guo S. Thermal-mechanical coupling model of contacting mechanical seal and sealing performance analysis[D]. Hangzhou: Zhejiang University of Technology, 2021.
[26]	唐飞翔, 孟祥铠, 李纪云, 等. 基于质量守恒的LaserFace液体润滑机械密封数值分析[J]. 化工学报, 2013, 64(10): 3694-3700.
	Tang F X, Meng X K, Li J Y, et al. Numerical analysis of LaserFace liquid lubricated mechanical seal based on mass conservation[J]. CIESC Journal, 2013, 64(10): 3694-3700.
[27]	Suresh M S. Development of turbopump systems for cryogenic and semicryogenic propulsion systems of ISRO[J]. Transactions of the Indian National Academy of Engineering, 2021, 6(2): 229-241.
[28]	Choukekar K D, Nandi T K. Hydrostatic journal bearings for cryogenic rocket engine turbopumps: a review on the developments[J]. Journal of the Institution of Engineers (India): Aerospace Engineering Journal, 2009, 9(1): 3-8.
[29]	Durham T F. Cryogenic Materials Data Handbook[M]. Washington: US Department of Commerce, 1961.
[30]	Burcham R E. Liquid Rocket Engine Turbopump Rotating-Shaft Seals[M]. Washington: National Aeronautics and Space Administration, 1978.