Mass Transfer Modeling into Disk Spaces of Heat Turbomachines

Abstract:

The thermal aerodynamic analysis of the processes in thermal turbomachinery is of great importance when it comes their design and operation in order to achieve reliable and trouble-free operation in the required turbo-power range. The distribution of kinematic and thermodynamic parameters of the working medium around heavy loaded working disks and labyrinth seals has a significant influence on heat-mass exchange and energy transformation processes. Object of this work is thermo-aerodynamic research of mass exchange processes associated with the movement of the working medium in typical complex clearances between the rotor and stator of the steam turbines of disk type and determining axial forces in the rotor. Results based on one-dimensional and two-dimensional formulations of the problem are analyzed and compared with the results of field experiment of turbine P12-90 / 18, which before the reconstruction had problems with unstable axial loading during operation in wide power range. After proper reconstruction the turbine is in a sustainable balance throughout the whole range of operation modes. There is consistency in the results in quantitative and qualitative terms regarding the extreme conditions of axial loading. There is a three-dimensional approach to solving the problem of distribution of axial loading on the structural elements of the rotor, whose advantage is the obtaining of a detailed picture of the passing fluid in the clearances between the rotor and stator of the aggregate and diaphragm-disk spaces, and a detailed presentation of the uneven distribution of the axial forces on the front surfaces. The applied thermal aerodynamic approach allows to predict the main characteristics of steam turbines at different axial and radial clearances, changing during the operation in case of wear of the the crest of the labyrinth seals. This approach can serve as a thermo-aerodynamic diagnosis of the condition of the flow part of different thermal turbomachinery and in variable working modes.

• Periodical: Defect and Diffusion Forum (Volume 362)
• Pages: 1-12
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.362.1
• Online since: April 2015
• Authors: Nikolay Lazarovski, Paskal Novakov, Anastas Yangyozov
• Keywords: Axial Loading, Ejection Effect, FEM, Pump Effect, Steam Pressure Area, Velocity

References

[1] R P. Roy, G. Xu, J. Feng, S. Kang, Pressure field and main-stream gas ingestion in a rotor-stator disk cavity, Department of Mechanical and Aerospace Engineering Tempe, Proceedings of ASME TURBO EXPO 2001, June 4-7, 2001, New Orleans, Louisiana.

DOI: 10.1115/2001-gt-0564

[2] L. Moroz, A. Tarasov, Flow phenomenon in steam turbine disk-stator cavities channeled by balance holes, SoftInWay Inc. Proceedings of ASME Turbo Expo 2004 Power for Land, Sea, and Air June 14-17, 2004, Vienna, Austria.

DOI: 10.1115/gt2004-54228

[3] Piotr Lampart, Andrzej Gerdzilewicz, Sergey Yershov, Andrey Rusanov, Investigations of flow characteristics of an HP turbine stage including the effect of tip leakage and windage flows using a 3d navier-stokes solver withsource/sink-type boundary conditions, Proceedings of 2000 International Joint Power Generation Conference Miami Beach, Florida, July 23-26, (2000).

DOI: 10.1007/s11630-001-0019-4

[4] Toshio Hirano, Zenglin Guo, R. Gordon Kirk, Application of CFD analysis for rotating machinery, part 2: labyrinth seal analysis, Proceedings of ASME Turbo Expo 2003 Power for Land, Sea, and Air, June 16–19, 2003, Atlanta, Georgia, USA.

DOI: 10.1115/gt2003-38984

[5] L. Moroz, A. Tarasov, Coupled CFD and thermal steady state analysis of steam turbine secondary flow path, SoftInWay Inc, IJPGC 2003 International Joint Power Generation Conference June 16-19, 2003, Atlanta, Georgia, USA.

DOI: 10.1115/ijpgc2003-40058

[6] I. I. Kirillov, A. I. Kirillov, Theory of Turbomachines, St. Petersburg, Machinostroenie, (1978).

[7] ANSYS. Theory Reference. Release 5. 5, 5. 6. Canonsburg, PA15317, 1998, (1999).

[8] ANSYS CFX Release 11. 0, December, (2006).

[9] R. D. Iosifov, N. A. Lazarovski, G. B. Nachev, I. K. Tudjarov, V. M. Gutsuzjan, Analysis and Evaluation of the Unstable Action for Steam Turbine Aggregate R 12-90/18. Seminar for Technical Maintenance of the Steam Turbine Aggregates, Stara Zagora, Bulgaria, (2001).