Analysis of contacless seal type impact on the pump characteristics of а rocket engine turbo-pump unit while operating mode changing

Aeronautical and Space-Rocket Engineering

To the 100th anniversary of B.V. Ovsyannikov


DOI: 10.34759/vst-2021-3-33-45

Аuthors

Ivanov A. V.

NPO Energomash named after academician V.P. Glushko, 1, Burdenko str., Khimki, 141400, Russia

e-mail: iav308@inbox.ru

Abstract

Pump seals of liquid rocket engines turbo-pump units are the key element defining the pump volumetric efficiency. The seal type selection herewith affects not only characteristics, but the pump operability as well. Both contactless and wearing-in seals are being employed in the liquid rocket engines turbo-pumps. The article considered the contactless seals, such as seals with floating and semi-movable rings, groove seal with fixed smooth wall and labyrinth seals, as the seals most frequently employed in the pumps structure.

Very often, the gap in the seal is being considered as a constant value while the pump operation analysis on the engine regulation modes. This was substantiated for the pumps of the engines operating without the generator gas afterburning behind the turbine, when delivery pressure and peripheral velocities were relatively small and, consequently, the level of seal elements deformation, both rotor and stator, was not high. It allowed not accounting for their impact on the gap value and leakages (consumption) through the seal. Transition to the engines with generator gas afterburning was accompanied by the pressure and peripheral velocities growth. It led to the necessity of accounting for the deformation of seal structure elements impact on its characteristics. The necessity for the engine operation regulation, including both forcing and throttling modes by thrust from 25 to 120% of the rated value required knowing the pumps parameters on all operation modes.

Another task during design is selection of the clearance size, ensuring the contactless operation of seal in all engine’s operating modes, from chill-down to its shutdown.

Thus, while the seals design of the pumps’ air-gas channel, the two types of gaps should be determined on all operation modes: the working gap determining consumption characteristics of the seal, i.e. the pump volumetric efficiency, and minimal guaranteed gap between rotor and stator seal elements, defining contactless operation conditions of the seal.

The article provides the dependencies for estimating the seal gap at the initial design stage.

The performed analysis demonstrates that already at the early design stages it is necessary to account for the seal gap impact on the pump efficiency with dependence on the operation mode.

The seal type selection exerts a substantial impact on the value of the seal guaranteed minimum gap. Thus, the analysis of its changing and permissible value should be performed beginning from the early design stages. The errors in the seal gap size selection may lead to modifying and necessity to the crucial changes of the structure.

Keywords:

non-contact seal, working clearance, minimum guaranteed clearance, rotary seal element

References

  1. Dmitrenko A.I., Ivanov A.V. Nauchno-tekhnicheskii yubileinyi sbornik KB Khimavtomatiki, Voronezh, IPF “Voronezh”, 2001, pp. 364–370.

  2. Chvanov V.K., Kashkarov A.M., Romasenko E.N., Tolstikov L.A. Trudy NPO Energomash, 2004, no. 22, pp. 81-99.

  3. Levochkin P.S., Chvanov V.K., Vasil’ev V.S., Timushev S.F. Vestnik Samarskogo universiteta. Aerokosmicheskaya tekhnika, tekhnologii i mashinostroenie, 2018, vol. 17, no. 4, pp. 81-92.

  4. Ivanov A.V. Aviatsionnye dvigateli, 2020, no. 1(6), pp. 39–48.

  5. Falaleev S.V. The Methodology for Calculating the Hydrodynamic Characteristics of a Mechanical Seal with Leakage Steam Formation. Journal of Friction and Wear, 2021, vol. 42, no. 1, pp. 50-55. DOI: 10.3103/S1068366621010037

  6. Badun O.P., Deshevykh S.A., Ivanov Ya.N. Vestnik dvigatelestroeniya, 2016, no. 2, pp. 115-121.

  7. Space Shuttle Main Engine Orientation, 1998, http://www.lpre.de/p_and_w/SSME/SSME_PRESENTATION.pdf

  8. Zhao Y., Wang C. Shape Optimization of Labyrinth Seals to Improve Sealing Performance. Aerospace, 2021, vol. 8, no. 4, p. 92. DOI: 10.3390/aerospace8040092

  9. Ivanov A.V., Belousov A.I., Dmitrenko A.I. Turbonasosnye agregaty kislorodno-vodorodnykh ZhRD (Turbopump units of oxygen-hydrogen liquid-propellant engines), Voronezh, VGTU, 2011, 283 s.

  10. Xu J., Li C., Miao X. et al. An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps. Chinese Journal of Mechanical Engineering, 2020, vol. 33, no. 1. Article id.26. DOI: 10.1186/s10033-020-00442-6

  11. Pfützenreuter L., De Almeida D., Pagliuco C. et al. Current Status on Joint L75 Engine Development with Focus on Turbopump Activities. 3AF Space Propulsion Conference. 2018, https://www.researchgate.net/publication/325595258

  12. Tokunaga Y., Inoue H., Hiromatsu J. et al. Rotordynamic Characteristics of Floating Ring Seals in Rocket Turbopumps. International Journal of Fluid Machinery and Systems, 2016, vol. 9, no. 3, pp. 194–204. DOI: 10.5293/IJFMS.2016.9.3.194

  13. Lee Y.B., Shin S.K., Ryu K. et al. Test Results for Leakage and Rotordynamic Coefficients of Floating Ring Seals in a High-Pressure, High-Speed Turbopump. Tribology Transactions, 2005, vol. 48, no. 3, pp. 273-282. DOI: 10.1080/05698190590948250

  14. Li G., Zhang Q., Huang E. et al. Leakage performance of floating ring seal in cold/hot state for aero-engine. Chinese Journal of Aeronautics, 2019, vol. 32, no. 9, pp. 2085-2094. DOI: 10.1016/j.cja.2019.03.004

  15. Liu Zh., Xia P., Zhang G. et al. Floating-ring seals movement mechanism and its influence on stability of a rotor system. Journal of Shock and Vibration, 2016, vol. 35, no. 9, pp. 110-116.

  16. Ovsyannikov B.V., Borovskii B.I. Teoriya i raschet agregatov pitaniya zhidkostnykh raketnykh dvigatelei (Theory and calculation of power units for liquid rocket engines), Moscow, Mashinostroenie, 1986, 376 p.

  17. Sulinov A.V., Shabliy L.S., Zubanov V.M. Simulation Methodology of the Screw-Centrifugal Pump for Liquid Hydrogen. Journal of Physics: Conference Series, 2017, vol. 803. DOI: 10.1088/1742-6596/803/1/012161

  18. Nazarov V.P., Yatsunenko V.G., Kolomentsev A.I. Constructive and technological factors of stability of energy parameters in turbopump assemblies of rocket engines. Aerospace MAI Journal, 2014, vol. 21, no. 5, pp. 101-105.

  19. Andriievskyi M.V., Mitikov Y.O. Influence of propellant leakage from pump area into turbine area on turbo-pump operation stability. Space Science and Technology, 2021, vol. 27, no. 1, pp. 97-102. DOI: 10.15407/knit2021.01.097

  20. Zhang K., Jiang X., Li S. et al. Transient CFD Simulation on Dynamic Characteristics of Annular Seal under Large Eccentricities and Disturbances. Energies, 2020, vol. 13, no. 16. DOI: 10.3390/en13164056

  21. Katorgin B.I., Semenov V.I., Chvanov V.K., Chel’kis F.Yu. Trudy NPO Energomash imeni akademika V.P. Glushko, 2003, no. 21, pp. 150-171.

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