UDK 621.454.2
INFLUENCE OF LAUNCH PARAMETERS OF LIQUID ROCKET ENGINE ON THE BALANCE OF AXIAL FORCES IN THE TURBOPUMP
E. N. Belayev, A. G. Vorobyev
Moscow Aviation Institute (National Research University) 4, Volokolamskoe Sh., Moscow, A-80, 125993, Russian Federation
In the process of launching a liquid rocket engine (LRE) and on the modes of its deep throttling of thrust, the problem of balance of axial forces in the turbo-pump assembly (TPA) is the most important. The reason is the pumps and turbine work of the engine in non-nominal modes, and, consequently, the appearance of unbalanced excess of axial forces acting on the bearings of TPA. To reduce the axial loads in the TPA, an automatic discharge device (ADD) is used, the task of which is to reduce the axial impact on the bearings due to the action of hydrodynamic forces. In the process of working in the ADD, friction of the surfaces, which forms a hydraulic gap, is not allowed, otherwise it can lead to the local combustion. The object of influence is LRE RD-120 developed by “NPO Energomash named after academician V. P. Glushko” [1], working on liquid oxygen-kerosene components, with afterburning of the oxidizing gas-generating gas scheme. The pneumatic-hydraulic scheme of the engine, the TPA design, the working principle of automatic discharge device are presented. Using the example of the LRE RD-120, the effect of axial forces acting on the angular contact ball bearing located on the side of the turbine TPA is considered. When the engine was developed, it was established that under some launch conditions it is possible to contact surfaces in the discharge device. In the article authors identify the conditions of contact in ADD and try to study the effect of the launch parameters of the LRE on the gap size of the working surfaces in the discharge device. For the theoretical analysis of the problem, a dynamic mathematical model of a liquid rocket engine is used. Mathematical modeling of engine start-up with nominal and early entry into operation of the combustion chamber was studied. The results show that with early starts of combustion chamber, there is a significant temperature rise in the gas generator, which can lead to the ignition of the nozzle or blades of the TPA turbine. Modeling the launch of the LRE with a change in the closing pressure of the oxidant supply valve to the pre-pump turbine booster, shows that this provides a longer operation of the oxidizer pump with a reduced hydraulic head, and allows changing the balance of axial forces during the engine launch and, as a result, prevent the full closure of the working gap in the ADD.
Keywords: liquid rocket engine, balance of axial forces, engine launch, turbo-pump assembly, automatic unloading device.
References

1. RD-120. Available at: http://www.npoenergomash.ru/ dejatelnost/engines/rd120/rd120_4.html (accessed: 24.04.2016).

2. Katherine Van Hooser, John Bailey, Alok Majumdar. Numerical prediction of transient axial thrust and internal flow in a rocket engine turbopump. AIAA-99-2189. Available at: https://gfssp.msfc.nasa.gov/zip/paper4_ aiaa99_2189.doc (accessed 01.05.2017).

3. Y. Demyanenko, A. Dmitrenko, V. Rachuk, A. Shostak A. Minick, R. Bracken, M. Buser. Single-Shaft Turbopumps in Liquid Rocket Engines. AIAA 2006-4377. Available at: www.rocket-propulsion.info/resources/.../AIAA-2005-3946 (accessed 01.05.2017).

4. Takashi Shimura, Satoshi Kawasaki, Masaharu Uchiumi, Jun Matsui. Internal flow and axial balancing of a Rocket pump. AJK2011-06027. Proceedings of the ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. AJK-Fluids. 2011.10 p.

5. Sherstjannikov V. Issledovanie dinamiki rotorov TNA ZhRD. [Investgation of dynamic of rotor turbopump liquid rocket engine). Available at: http://engine. aviaport.ru/issues/24/page18.html (accessed 01.05.2017).

6. Chvanov V. K., Fatuev I. Ju., Beljaev E. N. Dvigatel’ 11D123. Raschet dinamicheskiy. Chast’ pervaya. Raschet parametrov dvigatelya pri zapuske. [Engine 11D123. Calculation of dynamic. Part one. Calculation of parameters of engine during start on.] 00.1723.0000.0000.06.0P05, 2001г.

7. K unical’nyim razrabotkam [To unique design]. Available at: http://epizodsspace.airbase.ru/bibl/kb-ujn/05.html (accessed 19.01.2016).

8. Fatuev I. Yu. Issledovaniya problem, svyazannyih s modifikatsiey dvigatelya RD-120 dlya pervyih stupeney raket-nositeley kommercheskogo naznacheniya. Dis kand. tekhn. nauk [Research of problem of modification RD-120 rocket engine for using 1-st stage of commercial applied rocket. Cand. Diss.]. Moscow, MAI, 2003, 182 p.

9. Vasilev A. P., Kudryavtsev V. M., Kurpatenkov V. D. Osnovyi teorii i raschyota zhidkostnyih raketnyih dvigateley [Basic theory and calculation of liquid rocket engines]. Moscow, Vyisshaya shkola Publ., 1975, 656 p.

10. Katorgin B. I., Chvanov V. K., Belyaev E. N. [The numerical modeling of modern LRE]. Dvigatel. 2002, Vol. 4, P. 13–15 (In Russ.).

11. Dobrovolskiy M. V. Zhidkostnyie raketnyie dvigateli [Liquid rocket engines]. Moscow, MGTU im. N. E. Baumana Publ., 2006, 488 p.

12. Gahun G. G., Baulin V. I. et al. Konstrukciya i proektirovanie zhidkostnyx raketnyx dvigateley [Design and development liquid rocket engine: handbook for student of high school of aviation engine and power stand specialization ]. Moscow, Mashinostroenie Publ., 1989. 424 p.

13. Lebedinskiy E. N., Mosolov S. V., Kalmyikov G. P. Konstruktsiya i proektirovanie zhidkostnykh raketnykh dvigateley [The computational momels of liquid rocket engines]. Moscow, Mashinostroenie Publ., 2009, 375 p.

14. Ovsjannikov B. V., Borovskij B. I. Teoriya i raschet agregatov pitaniya zhidkostnykh raketnykh dvigateley [Theory and calculation of turbopump of liquid rocket engine]. Moscow, Mashinostroenie Publ., 1986, 376 p.

15. Belyaev E. N., Chvanov V. K., Chervakov V. V. Matematicheskoe modelirovanie ZhRD [The computational modelng of LRE]. Moscow, MAI Publ., 2009, 280 p.


Belayev Evgenyi Nikolaevich – Cand. Sc., Docent, Department of Energyphysical systems, Moscow Aviation

Institute (National Research University). E-mail: belyaev72@rambler.ru.

Vorobyev Alexey Gennadievich – Cand. Sc., Docent, Department of Rocket engines, Moscow Aviation Institute

(National Research University). E-mail: formula1_av@mail.ru.