Aerospace Technic and Technology

The subject of study in this article is the cost-effectiveness of the rotors of powerful turbines and their fire safety. Improvement of these indicators is possible by replacing oil lubrication systems with environmentally adaptive lubricants (EAL), in particular water or aqueous solutions. The main disadvantage of using water and other low-viscosity aqueous solutions for operating plain bearings is the lack of a hydrodynamic effect at low speeds of the rotor during start and stop of the turbine. The current study experimentally studies the possibility of replacing oil lubrication systems with EAL, in particular water or aqueous solutions. The objectives of the study: 1) to ensure that in the operating range of speeds and loads, the bearing operates in a stable hydrodynamic mode; 2) show that the use of a hydrostatic lifting system provides a liquid mode of friction in the range under study of loads and sliding speeds; 3) to determine the level of pressures at which the rotor rises. When solving this problem, the following methods were used. On the experimental stand, a full-scale radial bearing with babbitt filling of the working surface of the liner was tested. During the experiment, the following parameters were varied and measured: rotor speed, bearing load, lubricant consumption, working fluid temperature in front of and out of the bearing, water pressure (condensate) in the hydraulic system, pressure in the lubricating layer and chambers of the bearing. The main parameter by which the efficiency of the bearing was evaluated was the thickness of the lubricating layer of the working fluid. The following results were obtained. In the first stage, when the speed of the rotor is zero, the value of the pressure of the fluid supply, which ensures the emergence of the shaft. In the second stage, the dependence of the relative eccentricity on the shaft speed and the speed at which it is possible to turn off the rotor lifting system. Conclusions. In the investigated range of speed and loads, the bearing operated in a stable hydrodynamic mode. The use of a hydrostatic lifting system provided a liquid mode of friction in the range under study of sliding speeds (including starting and stopping the rotor). The temperature of the working surface of the bearing in a stable hydrodynamic mode depends little on the external load and sliding speed.

radial plain bearing; water lubrication; experimental research

Shvecov, V. L., Galacan, V. N. Raboty OAO «Turboatom» po modernizacii i sovershenstvovaniju turbin AJeS [Works of JSC "Turboatom" on the modernization and improvement of NPP turbines]. Jenergeticheskie i teplotehnicheskie processy i oborudovanie ‒ Energy and heat engineering processes and equipment, 2007, no. 2, pp. 6-10.

Somberg, J., Saravanan, P., Vadivel, H. S., Berglund, K., Shi, Y., Ukonsaari, J., Emami, N. Tribological characterisation of polymer composites for hydropower bearings: experimentally developed versus commercial materials. Tribology International, 2021, vol. 162, article id 107101. DOI: 10.1016/j.triboint.2021.107101.

Du, Fengming., Chen, Changduo., Zhang, Kaiguang. Fluid Characteristics Analysis of the Lubricating Oil Film and the Wear Experiment Investigation of the Sliding Bearing. Coatings, 2022, vol. 12, iss. 1, article id 67. DOI: 10.3390/coatings12010067.

Cao, Jun., Qin, Liang., Yu, Aibing. et al. A Review of Surface Treatments for Sliding Bearings Used at Different Temperature. Friction, Lubrication and Wear, London, IntechOpen, 2019, pp. 1-24. DOI: 10.5772/intechopen.86304.

Golchin, A., Simmons, G. F., Glavatskih, S., Prakash, B. Tribological behaviour of polymeric materials in water-lubricated contacts. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2013, vol. 227, iss. 8, pp. 811-825. DOI: 10.1177/1350650113476441.

Lur'e, Z. Ja., Gasjuk, A. I., Dinamika sistemy gidrostaticheskogo pod’ema vala parovoj turbiny [Dynamics of the hydrostatic lifting system of the steam turbine shaft]. Vіsnik KDPU іm. M. Ostrograds'kogo, Kyiv State Polytechnic University Bulletin, 2008, vol. 2 (49), part 2, pp. 85-88.

Buchhorn, N., Kukla, S., Bender, B., Neumann, M. Tilting-Pad Journal Bearing in Hybrid Operation: A Numerical and Experimental Investigation. Proceedings of the ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. Oslo, Norway. June 11–15, 2018, vol. 7B: Structures and Dynamics, paper No: GT2018-75256, V07BT34A007. 11 p. DOI: 10.1115/GT2018-75256.

Bouyer, J., Wodtke, M., Fillon, M. Experimental research on a hydrodynamic thrust bearing with hydrostatic lift pockets: Influence of lubrication modes on bearing performance. Tribology International, 2022, vol. 165, article id 107253. DOI: 10.1016/j.triboint.2021.107253.

Micahlec, M., Svoboda, P., Křupka, I., Hartl, M. A review of the design and optimization of large-scale hydrostatic bearing systems. Engineering Science and Technology, an International Journal, 2021, vol. 24, iss. 4, pp. 936-958. DOI: 10.1016/j.jestch.2021.01.010.

Ivashhenko, E. I., Kantemir, A. D. Osnovnye osobennosti uslovij raboty radial'nyh podshipnikov skol'zhenija parovyh turbin bol'shoj moshhnosti [The main features of the operating conditions of radial plain bearings of high power steam turbines]. Vysokoskorostnye gidrostaticheskie opory dvigatelej letatel'nyh apparatov ‒ High-speed hydrostatic supports for aircraft engines, Kharkov, 1990, pp. 123-131.

Nazin, V. Determining the influence of structural and operational parameters of a double bearing on the thickness of its disc. Eastern-European journal of Enterprise Technologies, 2021, vol. 3, no. 7(111), pp. 68-73. DOI: 10.15587/1729-4061.2021.235284.

Artemenko, N. P., Docenko, V. N., Chajka, A. I. Gidrostaticheskie opory rotorov bystrohodnyh mashin [Hydrostatic rotor bearings for high-speed machines]. Kharkov, “Osnova” Publ., 1992. 196 p.

McCarthy, D. M. C., Glavatskih, S. B., Sherrington, I. Oil film thickness and temperature measurements in PTFE and babbitt faced tilting-pad thrust bearings, Proc. I. Mech. E., 2005, vol. 219, Part J: J. Engineering Tribology, pp. 179-185.

Wang, Q. J., Chung, Y.-W. Encyclopedia of Tribology. New York, Springer Publ., 2013. 4190 p. DOI: 10.1007/978-0-387-92897-5.

Сonstantinesсu, V. N. Analysis of bearings operating in turbulent regime. Journal of Basic Engineering, 1962, vol. 84, iss. 1, pp. 139-151. DOI: 10.1115/1.3657235.