The Efficiency Increase of the Steam Turbine Low Pressure Cylinder Last Stage by the Blades Spatial Profiling

Journal Journal of Mechanical Engineering
Publisher A. Podgorny Institute for Mechanical Engineering Problems
National Academy of Science of Ukraine
ISSN 0131-2928 (Print), 2411-0779 (Online)
Issue Vol. 23, no. 1, 2020 (March)
Pages 6-14
Cited by J. of Mech. Eng., 2020, vol. 23, no. 1, pp. 6-14



Andrii V. Rusanov, A. Podgorny Institute of Mechanical Engineering Problems of NASU (2/10, Pozharskyi St., Kharkiv, 61046, Ukraine), e-mail:, ORCID: 000-0003-1345-7010

Viktor L. Shvetsov, Joint-Stock Company Turboatom (199, Moskovskyi Ave., Kharkiv, 61037, Ukraine), e-mail: ORCID: 0000-0002-2384-1780

Svitlana V. Alyokhina, A. Podgorny Institute of Mechanical Engineering Problems of NASU (2/10, Pozharskyi St., Kharkiv, 61046, Ukraine), V. N. Karazin Kharkiv National University, (4, Svobody Sq., Kharkiv, 61022, Ukraine), e-mail:, ORCID: 0000-0002-2967-0150

Natalia V. Pashchenko, A. Podgorny Institute of Mechanical Engineering Problems of NASU, (2/10, Pozharskyi St., Kharkiv, 61046, Ukraine), e-mail:, ORCID: 0000-0002-3936-7331

Roman A. Rusanov, A. Podgorny Institute of Mechanical Engineering Problems of NASU (2/10, Pozharskyi St., Kharkiv, 61046, Ukraine), e-mail:, ORCID: 0000-0003-2930-2574

Mykhailo H. Ishchenko, Joint-Stock Company Turboatom (199, Moskovskyi Ave., Kharkiv, 61037, Ukraine), e-mail:, ORCID: 0000-0003-2251-5104

Liubov O. Slaston, Joint-Stock Company Turboatom (199, Moskovskyi Ave., Kharkiv, 61037, Ukraine), e-mail:, ORCID: 0000-0002-9268-8134

Riza B. Sherfedinov, Joint-Stock Company Turboatom (199, Moskovskyi Ave., Kharkiv, 61037, Ukraine), e-mail:, ORCID: 0000-0002-5947-7802



The paper presents an option of the steam condensing turbine K-325-23.5 (K-300 series) low pressure cylinder flow part improvement due to the last stage modernization. The K-325-23.5 turbine is designed to replace the outdated K-300 series turbines, which together with the K-200 series turbines form the basis of Ukraine’s thermal energy. In the modernized flow part, new last stage guide apparatus blades with a complex circular lean near the hub are used. The purpose of the modernization was to increase the low-pressure cylinder efficiency in the “bad” condenser vacuum to ensure that it did not “decrease” its efficiency at rated operating modes. The modernized low-pressure cylinder flow part is developed with the usage of modern methods of the viscous three-dimensional flow calculation based on the numerical integration of the Reynolds-averaged Navier-Stoks equations. For the turbulent effects, a two-parameter differential SST Menter turbulence model is applied, and for the hydraulic fluid real properties, the IAPWS-95 state equation is used. To construct the axial blades three-dimensional geometry, the original method, the initial data for which was the limited number of parameterized quantities, was used. The applied methods of gas-dynamic calculations and design of flow turbomachines are implemented in the IPMFlow software package, which is the development of the FlowER and FlowER-U software packages. The researched low-pressure cylinder flow part is limited by the last two stages (4th and 5th). A difference grid with a total element volume of more than 3 million is used to construct the calculation area. The research examined more than 20 options of the last stage stator blades. In the modernized flow part of the low-pressure cylinder last stage at rated operating mode, the gain of the efficiency coefficient (efficiency) is 0.9% and power – 0.61 MW. In the mode of “bad” condenser vacuum (with high pressure) a significant increase is achieved: efficiency – by 11.5%, power increased by almost 2 MW.


Keywords: spatial profiling, numerical modeling, spatial flow, gas-dynamic efficiency, steam turbine, last stage.


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Received 24 February 2020

Published 30 March 2020