|Journal||Journal of Mechanical Engineering – Problemy Mashynobuduvannia|
|Publisher||A. Pidhornyi Institute for Mechanical Engineering Problems
National Academy of Science of Ukraine
|ISSN||2709-2984 (Print), 2709-2992 (Online)|
|Issue||Vol. 24, no. 4, 2021 (December)|
|Cited by||J. of Mech. Eng., 2021, vol. 24, no. 4, pp. 61-70|
Andrii S. Koliadiuk, SE «State Science and Engineering Center for Control Systems and Emergency Response» (64/56, Heroiv Stalinhradu ave., Kyiv, 04213, Ukraine), e-mail: firstname.lastname@example.org, ORCID: 0000-0003-2946-272X
Mykola H. Shulzhenko, A. Pidhornyi Institute of Mechanical Engineering Problems of NASU (2/10, Pozharskyi str., Kharkiv, 61046, Ukraine), e-mail: email@example.com, ORCID: 0000-0002-1386-0988
Oleksandr M. Hubskyi, Joint-Stock Company “Ukrainian Energy Machines” (formerly JSC “Turboatom”) (199, Moskovskyi ave., Kharkiv, 61037, Ukraine)
The stability of operation of steam turbines depends (along with other factors) on the reliable operation of their steam distribution systems, which are based on stop and control valves. This paper considers the strength of the elements of the K-325-23.5 steam turbine valves, in whose bodies, after 30 thousand hours of operation, cracks came to be observed. Previously determined were the nature of gas-dynamic processes in the flow paths of the valves and the temperature state of the valve body in the main stationary modes of operation. To do this, a combined problem of steam flow and thermal conductivity in stop and control valves was solved in a three-dimensional formulation by the finite element method. Different positions of the valve elements were considered taking into account the filter sieve. The assessment of the thermal stress state of the valve body showed that the maximum stresses in different operating modes do not exceed the yield strength. Therefore, the assessment of the creep of the valve body material is important to determine the valve body damage and service life. Modeling the creep of the stop and control valves of the turbine was performed on the basis of three-dimensional models, using the theory of hardening, with the components of unstable and steady creep strains taken into account. The creep was determined at the maximum power of the turbine for all the stationary operating modes. The maximum calculated values of creep strains are concentrated in the valve body branch pipes before the control valves and in the steam inlet chamber, where in practice fatigue defects are observed. However, even for 300 thousand hours of operation of the turbine (with a conditional maximum power) in stationary modes, creep strains do not exceed admissible values. The damage and service life of the valve bodies were assessed by two methods developed at A. Pidhornyi Institute of Mechanical Engineering Problems of the NAS of Ukraine (2011), and I. Polzunov Scientific and Design Association on Research and Design of Power Equipment. (NPO CKTI) – 1986. The results of assessing the damage and the turbine valve body wear from the effects of cyclic loading and creep of the turbine in stationary modes for 40, 200 and 300 thousand hours show that the thermal conditions of the body in the steam inlet chamber are not violated (without taking into account possible body defects after manufacture). The damage in valve body branch pipes after 300 thousand hours of operation exceeds the admissible value, with account taken of the safety margin. At the same time, the damage from creep in stationary operating modes is about 70% of the total damage. The maximum values of damage are observed in the areas of the body where there are defects during the operation of the turbine steam distribution system. The difference between the results of both methods in relation to their average value is ~20%.
Keywords: stop and control valve, steam distribution system, finite element method, thermal stress, creep, cyclic fatigue, service life.
Full text: Download in PDF
- Sudakov, A. V., Gavrilov, S. N., Georgiyevskaya, Ye. V., Levchenko, A. I., & Fedorova, L. V. (2015). Obosnovaniye prodleniya sroka sluzhby parovykh turbin, imeyushchikh detali s otkloneniyami ot trebovaniy normativnoy dokumentatsii [Justification for extending the service life of steam turbines with parts with deviations from the requirements of regulatory documents]. Neftegaz.RU, vol. 2, no. 1–2, pp. 42–47 (in Russian).
- Shulzhenko, N. G., Gontarovskiy, P. P., & Zaytsev, B. F. (2011). Zadachi termoprochnosti, vibrodiagnostiki i resursa energoagregatov (modeli, metody, rezultaty issledovaniy) [Problems of thermal strength, vibrodiagnostics and resource of power units (models, methods, results of research)]. Saarbrücken, Germany: LAP LAMBERT Academic Publishing GmbH & Co. KG, 370 p. (in Russian).
- Wang, W., Xu, S., & Liu, Y. (2017). Numerical investigation of creep-fatigue behavior in a steam turbine inlet valve under cyclic thermomechanical loading. Journal of Engineering for Gas Turbines Power, vol. 139, iss. 11, article ID 112502. https://doi.org/10.1115/1.4036953.
- Rusin, A. (1992). Numerical simulation of turbine valve creep. Archive of Applied Mechanics, vol. 62, pp. 386–393. https://doi.org/10.1007/BF00804599.
- Kolyadyuk, A. S., Shulzhenko, N. G., & Yershov, S. V. (2012). Techeniye para i raspredeleniye temperatury v sisteme paroraspredeleniya turbiny dlya razlichnykh rezhimov yeye raboty [Steam flow and temperature distribution in the turbine steam distribution system for different modes of its operation]. Aviatsionno-kosmicheskaya tekhnika i tekhnologiya – Aerospace Engineering and Technology, no. 7 (94), pp. 85–90 (in Russian).
- Koliadiuk, A. S. & Shulzhenko, M. H. (2019). Thermal and stress state of the steam turbine control valve casing, with the turbine operation in the stationary modes. Journal of Mechanical Engineering – Problemy Mashynobuduvannia, vol. 22, no 2, pp. 37–44. https://doi.org/10.15407/pmach2019.02.037.
- Howard, G. J. (2017). Finite element modelling of creep for an industrial application. Dissertation (MEng). University of Pretoria, 89 p.
- Shulzhenko, N. G. & Kolyadyuk, A. S. (2015). Otsenka vliyaniya formy kamery na techeniye para i na polzuchest korpusa reguliruyushchego klapana turbiny [Evaluation of the effect of the chamber shape on the steam flow and on the creep of the turbine control valve body]. Problemy mashinostroyeniya – Journal of Mechanical Engineering – Problemy Mashynobuduvannia, vol. 18, no. 3, pp. 45–53 (in Russian).
- Shulzhenko, M. & Koliadiuk, A. (2021). Termonapruzhenist, povzuchist i resurs korpusu stoporno-rehuliuvalnykh klapaniv parovoi turbiny [Thermal stress, creep and service life of the steam turbine shut-off valve body]. Proceedings of the 15th International Symposium of Ukrainian Mechanical Engineers in Lviv, pp. 24–27 (in Ukrainian). https://doi.org/10.15407/pmach2021.04.061.
- Shulzhenko, M. H., Hontarovskyi, P. P., Matiukhin, Yu. I., Melezhyk, I. I., & Pozhydaiev, O. V. (2011). Vyznachennia rozrakhunkovoho resursu ta otsinka zhyvuchosti rotoriv i korpusnykh detalei turbin [Determination of estimated resource and evaluation of rotor life and body parts of turbines]: Methodological guidelines. Regulatory document SOU-N MEV 0.1–21677681–52:2011: Approved by the Ministry of Energy and Coal Mining of Ukraine: Effective as of 07.07.11. Kyiv: Ministry of Energy and Coal Mining of Ukraine, 42 p. (in Ukrainian).
- (1985). Detali parovykh statsionarnykh turbin. Raschot na malotsiklovuyu ustalost [Details of steam stationary turbines. Calculation of low-cycle fatigue]. Technical Guidance RTM no. 108.021.103-85, approved and implemented at the direction of the Ministry of Power Engineering of 13.09.85, no. AZ-002/7382. Moscow, 49 p. (in Russian).
- Nikols, R. (1975). Konstruirovaniye i tekhnologiya izgotovleniya sosudov davlennya [Design and manufacturing technology of pressure vessels]. Moscow: Mashinostroyeniye, 464 p. (in Russian).
- (1986). OST 108.020.132-85. Turbiny parovyye statsionarnyye. Normy rascheta na pochnost korpusov tsilindrov i klapanov [Stationary steam turbines. Standards for calculating the strength of cylinder bodies and valves]. Moscow: Ministry of Power Engineering, 31 p. (in Russian).
- Troshchenko, V. T. & Sosnovskiy, L. A. (1987). Soprotivleniye ustalosti metallov i splavov [Fatigue resistance of metals and alloys]. Kiyev: Naukova Dumka, 284 p. (in Russian).
- Perevezentseva, T. V., Zlepko, V. F., & Kalugin, R. N. (2002). Strukturnyye osobennosti i zharoprochnost metalla tsentrobezhnolitykh trub iz stali 15KH1M1F [Structural features and heat resistance of the metal of centrifugally cast pipes made of steel 15H1M1F]. Teplovyye yelektrostantsii – Thermal power plants, no. 6, pp. 47–53 (in Russian).
- (1979). OST 108.961.02-79. Otlivki iz uglerodistykh i legirovannykh staley dlya detaley parovykh statsionarnykh turbin s garantirovannymi kharakteristikami prochnosti pri vysokikh temperaturakh [OST 108.961.02-79. Carbon and alloy steel castings for stationary steam turbine parts with guaranteed strength characteristics at high temperatures]: Technical conditions. NPO CNIITMash, NPO CKTI, 48 p. (in Russian).
- (2008). Turbina parovaya K-325-23.5. Tipovyye tekhnicheskiye usloviya TU U 29.1-05762269-025:2011. Instruktsiya po prodleniyu sroka ekspluatatsii parovykh turbin sverkh parkovogo resursa: SO 153-34.17.440-2003 [Steam turbine К-325-23.5. Typical technical conditions. TU U 29.1-05762269-025: 2011. Instructions for extending the service life of steam turbines beyond design service life: SО 153-34.17.440-2003]. Moscow: JSC “STC “Industrial Safety”, 158 p. (in Russian).
Received 06 October 2021
Published 30 December 2021