Methods for flow separation prevention on external contour at high expansion angles of steam turbine flow path
Abstract
Most thermal and nuclear power plants use a steam turbine to convert steam potential energy into mechanical work on therotating rotor. To operate the steam turbine at high efficiency, the aerodynamic losses in the flow path must be decreased,especially in a low-pressure turbine (LPT). This study focuses on the problem of flow separation in the area of the externalcontour, occurring at high expansion angles of the flow path and constituting a principal cause of flow non-uniformity upstreamof the nozzle assembly. Under specific flow conditions, the nozzle assembly peripheral area can be blocked by concentratedvortex, resulting in a sharp increase in losses. A numerical study and comparative analysis of two solutions to this problemwere conducted. Quantitative evaluation of nozzle blade cascade energy loss reduction showed that the flow suction onthe external surface of a wide-angle diffuser is the most effective in the case of removal of 2% of total flow, using holeslocated in the middle of an annular diffuser. In this case, the loss coefficient of nozzle blade cascade was reduced by 2.1%.Enhancement of LPT flow path, by mounting an aerodynamic deflector in a wide-angle diffuser, led to a 3% decrease in theloss coefficient. The research results lead to the conclusion that energy losses caused by high expansion angles of LPT flowpath can be reduced by applying the considered methods to prevent flow separation on the external contour upstream of thenozzle assembly.References
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power plant with measured boiler and turbine losses, Applied Thermal
Engineering 30 (8-9) (2010) 970–976.
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T. Miyawaki, M. Tsutsumi, T. Shinohara, Development of new high efficiency
steam turbine, Mitsubishi Heavy Ind. Tech. Rev. 40 (4) (2003)
6.
[3] A. Chaibakhsh, A. Ghaffari, Steam turbine model, Simulation Modelling
Practice and Theory 16 (9) (2008) 1145–1162.
[4] M. Häfele, J. Starzmann, M. Grübel, M. Schatz, D. Vogt, R. Drozdowski,
L. Völker, Numerical investigation of the impact of partspan
connectors on aero-thermodynamics in a low pressure industrial
steam turbine, in: ASME Turbo Expo 2014: Turbine Technical Conference
and Exposition, American Society of Mechanical Engineers,
2014, pp. V01BT27A004–V01BT27A004.
[5] V. Michelassi, L.-W. Chen, R. Pichler, R. D. Sandberg, Compressible
direct numerical simulation of low-pressure turbines part ii: Effect of inflow
disturbances, Journal of Turbomachinery 137 (7) (2015) 071005.
[6] D. Lengani, D. Simoni, Recognition of coherent structures in the
boundary layer of a low-pressure-turbine blade for different free-stream
turbulence intensity levels, International Journal of Heat and Fluid Flow
54 (2015) 1–13.
[7] J. Starzmann, M. M. Casey, J. F. Mayer, F. Sieverding, Wetness loss
prediction for a low pressure steam turbine using computational fluid
dynamics, Proceedings of the Institution of Mechanical Engineers, Part
A: Journal of Power and Energy 228 (2) (2014) 216–231.
[8] C. Hall, S. L. Dixon, Fluid mechanics and thermodynamics of turbomachinery,
Butterworth-Heinemann, 2013.
[9] A. Zaryankin, S. Arianov, V. Zaryankin, A. Pavlov, Prospects of using
two-tier low-pressure cylinders in steam-turbine power units, Thermal
engineering 56 (1) (2009) 50–56.
[10] A. Zaryankin, Two-tier low pressure cylinders for condensing steam
turbines, Transactions of the Institute of Fluid-Flow Machinery.
[11] K. Sangston, J. Little, M. E. Lyall, R. Sondergaard, End wall loss reduction
of high lift low pressure turbine airfoils using profile contouring
part ii: Validation, Journal of Turbomachinery 136 (8) (2014) 081006.
[12] R. Tindell, T. Alston, C. Sarro, G. Stegmann, L. Gray, J. Davids, Computational
fluid dynamics analysis of a steam power plant low-pressure
turbine downward exhaust hood, Journal of engineering for gas turbines
and power 118 (1) (1996) 214–224.
[13] M. Deich, A. Zaryankin, Gas dynamic of diffusors and exhaust hood,
Energiya, Moscow (1970) 384.
[14] J. Starzmann, M. Schatz, M. Casey, J. Mayer, F. Sieverding, Modelling
and validation of wet steam flow in a low pressure steam turbine, in:
ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition,
American Society of Mechanical Engineers, 2011, pp. 2335–
2346.
[15] V. Gribin, A. Tishchenko, I. Y. Gavrilov, V. Popov, I. Y. Sorokin,
V. Tishchenko, S. Khomyakov, Experimental study of intrachannel separation
in a flat nozzle turbine blade assembly with wet stream flow1,
Power Technology and Engineering 50 (2) (2016) 180–187.
[16] V. Gribin, A. Tishchenko, V. Tishchenko, I. Gavrilov, S. Khomiakov,
V. Popov, A. Lisyanskiy, A. Nekrasov, V. Nazarov, K. Usachev, An experimental
study of influence of the steam injection on the profile surface
on the turbine nozzle cascade performance, in: ASME Turbo Expo
2014: Turbine Technical Conference and Exposition, American Society
of Mechanical Engineers, 2014, pp. V01BT27A050–V01BT27A050.
[17] V. Solodov, A. Khandrymailov, V. Shvetsov, I. Kozheshkurt, V. Konev,
Investigation of aerodynamic and energy characteristics of lpc compartment
of stages with inlet pipe and leak system for powerful steam
turbine unit, The Bulletin of the National Technical University “Kharkiv
Polytechnic Institute” series: “Power and heat engineering processes
and equipment” (8).
[18] S. Miyake, I. Koda, S. Yamamoto, Y. Sasao, K. Momma, T. Miyawaki,
H. Ooyama, Unsteady wake and vortex interactions in 3-d steam turbine
low pressure final three stages, in: ASME Turbo Expo 2014: Turbine
Technical Conference and Exposition, American Society of Mechanical
Engineers, 2014, pp. V01BT27A013–V01BT27A013.
[19] J. Cui, V. N. Rao, P. Tucker, Numerical investigation of contrasting flow
physics in different zones of a high-lift low-pressure turbine blade, Journal
of Turbomachinery 138 (1) (2016) 011003.
[20] A. Zaryankin, Mechanics of compressible and incompressible flows,
MPEI (2014) 590.
[21] A. Zaryankin, V. Gribin, A. Paramonov, V. Noskov, O. Mitrokhova, The
effect the aperture angle of flat diffusers has on their vibration state and
ways for reducing this vibration, Thermal Engineering 59 (9) (2012)
674–682.
[22] A. Zaryankin, A. Rogalev, S. Osipov, V. Khudyakova, I. Komarov,
Method to flow parameters non-uniformity reduction in the afterextraction
stages of two-tier low-pressure turbine, International Journal
of Applied Engineering Research 11 (20) (2016) 10299–10306.
Published
2019-03-13
How to Cite
LISIN, Evgeny et al.
Methods for flow separation prevention on external contour at high expansion angles of steam turbine flow path.
Journal of Power Technologies, [S.l.], v. 99, n. 1, p. 10–14, mar. 2019.
ISSN 2083-4195.
Available at: <https://papers.itc.pw.edu.pl/index.php/JPT/article/view/990>. Date accessed: 21 dec. 2024.
Issue
Section
Power Plant
Keywords
Low-pressure turbine; External contour; Nozzle assembly; Boundary layer separation; Flow suction; Aerodynamic deflector; Loss coefficient
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