Material Engineering and Mechanical Manufacturing

Experiment on leakage flow characteristics of lubricating oil for a carbon seal system of bearing chamber based on air-bleeding oil-sealing mode

  • Liangyu HAN ,
  • Huan ZHAO ,
  • Cheng CHANG ,
  • Ping WANG ,
  • Dan SUN ,
  • Guozhe REN
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  • 1.Liaoning Key Lab of Advanced Test Technology for Aerospace Propulsion System,School of Aero-engine,Shenyang Aerospace University,Shenyang  110136,China
    2.Key Laboratory of Turbomachinery Advanced Seal Technology,Shenyang  110136,China
    3.AECC Sichuan Gas Turbine Establishment,Chengdu  610599,China

Received date: 2024-09-28

  Revised date: 2024-10-23

  Accepted date: 2024-11-25

  Online published: 2024-12-05

Supported by

National Natural Science Foundation of China(52375195);Fundamental Research Funds for Universities of Liaoning Province(LJ222410143090)

Abstract

Leakage of lubricating oil from carbon seal system of bearing chamber caused by insufficient seal pressure from compressor and excessive oil supply pressure of bearing chamber has an important effect on the operational stability of aero-engine. Based on air-bleeding oil-sealing mode, an experimental device was designed and built to simulate structure and working environment of the carbon seal system in bearing chamber of an actual aero-engine. Evolution process of oil leakage flow was visually observed. Effects of rotor speed and oil temperature on the critical oil-sealing pressure difference were experimentally studied. Leakage flow mechanism of oil through the carbon seal system in bearing chamber was revealed. Results show that as the sealing pressure difference gradually decreases, the lubricating oil initially from leaked the bottom of carbon seal ring, undergoing four processes: infiltration and backflow, increased infiltration, droplet-like leakage, and fluid-like leakage. The value of sealing pressure difference corresponding to that the droplet-like leakage occurred was considered as critical oil-sealing pressure difference of carbon seal system in bearing chamber. As rotor speed increased from 4 000 r/min to 12 500 r/min, the critical oil-sealing pressure difference decreased by 85.9%. At lower rotor speeds, the centrifugal force acting on the lubricating oil is relatively small, causing the oil to accumulate in clumps and fill the sealing gap. When the lubricating oil temperature increases from 40 ℃ to 121 ℃, the critical oil-sealing pressure difference decreased by 83.1%. At lower oil temperature, the density and dynamic viscosity of the oil increased, gravity and viscous acting on the oil increased, accumulation of the oil in seal clearance also increased.

Cite this article

Liangyu HAN , Huan ZHAO , Cheng CHANG , Ping WANG , Dan SUN , Guozhe REN . Experiment on leakage flow characteristics of lubricating oil for a carbon seal system of bearing chamber based on air-bleeding oil-sealing mode[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2025 , 46(10) : 431297 -431297 . DOI: 10.7527/S1000-6893.2024.31297

References

1 黎林林, 谢光华. 某型号涡喷发动机滑油系统设计[J]. 推进技术200122(6): 493-495.
  LI L L, XIE G H. Oil system design of a certain turbo-jet engine[J]. Journal of Propulsion Technology200122(6): 493-495 (in Chinese).
2 FLOUROS M. The impact of oil and sealing air flow, chamber pressure, rotor speed, and axial load on the power consumption in an aeroengine bearing chamber[J]. Journal of Engineering for Gas Turbines and Power2005127(1): 182-186.
3 航空发动机设计手册总编委会. 航空发动机设计手册:传动及润滑系统[M]. 北京: 航空工业出版社, 2002: 167-186.
  Chief Editorial Committee of Aviation Engine Design Manual. Aviation engine design manual: Transmission and lubrication systems[M]. Beijing: Aviation Industry Press, 2002: 167-186 (in Chinese).
4 MICHAELIS S. Oil bearing seals and aircraft cabin air contamination[J]. Sealing Technology2016, 2016(4): 7-10.
5 REN G Z, LI Y P, ZHAO H, et al. Research on oil-gas two-phase flow characteristics and improvement of aero-engine bearing chamber[J]. Lubricants202311(9): 360.
6 KURZ W, BAUER H J. An approach for predicting the flow regime in an aero engine bearing chamber[C]∥Turbo Expo: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2014.
7 孙恒超, 陈国定, 王莉娜, 等. 轴承腔油滴含率及油滴相与空气能量传递分析[J]. 航空学报201637(3): 1060-1073.
  SUN H C, CHEN G D, WANG L N, et al. Oil droplets fractions and oil droplets/air energy transfer analysis in bearing chamber[J]. Acta Aeronautica et Astronautica Sinica201637(3): 1060-1073 (in Chinese).
8 王莉娜, 陈国定, 孙恒超. 轴承腔油滴沉积特性及油膜流动特征分析[J]. 航空学报201637(10): 3159-3169.
  WANG L N, CHEN G D, SUN H C. Characteristics analysis of oil droplet deposition and oil film flow in a bearing cavity[J]. Acta Aeronautica et Astronautica Sinica201637(10): 3159-3169 (in Chinese).
9 任国哲. 基于油气两相流的航空发动机轴承腔流动换热研究及回油结构改进设计[D]. 西安: 西北工业大学, 2016: 48-53.
  REN G Z. Study on flow and heat transfer and optimization of scavenge structure in bearing chamber based on oil/air two-phase flow[D]. Xi’an: Northwestern Polytechnical University, 2016: 48-53 (in Chinese).
10 NICOLI A, JOHNSON K, JEFFERSON-LOVEDAY R. Simulation of a simplified aeroengine bearing chamber using a fully coupled two-way Eulerian thin film/discrete phase approach part I: Film behavior near the bearing[J]. Journal of Engineering for Gas Turbines and Power2021143(10): 101015.
11 NICOLI A, JOHNSON K, JEFFERSON-LOVEDAY R. Simulation of a simplified aeroengine bearing chamber using a fully coupled two-way Eulerian thin film/discrete phase approach part II: Droplet behavior in the chamber[J]. Journal of Engineering for Gas Turbines and Power2021143(10): 101016.
12 李炎军, 杨富, 刘振侠, 等. 轴承腔油气两相介质流动与热分析[J]. 航空动力学报202136(3): 606-615.
  LI Y J, YANG F, LIU Z X, et al. Flow and thermal analysis of oil air two-phase medium in bearing chamber[J]. Journal of Aerospace Power202136(3): 606-615 (in Chinese).
13 LI S B, LI C X, WANG W. Simulation of unsteady flows of oil/gas in the ventless bearing chamber of an aero-engine[J]. Aerospace20229(4): 211.
14 LU P, YE Q H, FANG L L, et al. Research on the air–oil two-phase flow regime in an aeroengine bearing chamber based on Hilbert-Huang transform[J]. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering2022236(1): 24-32.
15 FELIX C V P, MATTHIAS B K, CORINA H, et al. Experimental and numerical investigations on oil leakage across labyrinth seals in aero engine bearing chambers[C]∥Turbo Expo: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2016.
16 LI G, ZHANG Q, LEI Z, et al. Leakage performance of labyrinth seal for oil sealing of aero-engine[J]. Propulsion and Power Research20198(1): 13-22.
17 LI Z T, LI Y F, CAO H, et al. Investigation of cavitation evolution and hydrodynamic performances of oil film seal with spiral groove[J]. Tribology International2021157: 106915.
18 LIU F Y, YU B, LI Y F, et al. Experimental study on lubrication characteristics and leakage inhibition of oil-lubricated seal with herringbone grooves[J]. Tribology International2023187: 108751.
19 郭金道, 赵欢, 王平, 等. 基于引气封油方式的轴承腔密封间隙油气两相泄漏流动特性数值与试验研究[J]. 机械工程学报202460(3): 214-225.
  GUO J D, ZHAO H, WANG P, et al. Numerical and experimental study on oil-air two-phase leakage flow characteristics based on air-bleeding oil-sealing mode in seal clearance of bearing cavity[J]. Journal of Mechanical Engineering202460(3): 214-225 (in Chinese).
20 何彬, 马正军, 李卓, 等. 某型燃气轮机轴承腔压力异常分析及改进[J]. 热能动力工程202136(10): 187-192.
  HE B, MA Z J, LI Z, et al. Analysis and improvement of abnormal pressure in bearing cavity of a gas turbine[J]. Journal of Engineering for Thermal Energy and Power202136(10): 187-192 (in Chinese).
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