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Computer models of steam pipeline components in the evaluation of their local strength

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Wybrane pełne teksty z tego czasopisma
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Języki publikacji
EN
Abstrakty
EN
Purpose: The paper discusses the issue of modelling the heating and cooling processes of T-pipes in a power plant pipeline in the start-up conditions of a boiler. The main purpose of this work is the description of the mechanical behaviour of power plant components working under mechanical and thermal loading and validation of the computer modelling methods. Design/methodology/approach: The FEM modelling has been used to describe the local stress-strain behaviour of the chosen component. Findings: The reasons for the presence of high and variable in time temperature gradients in the components of the main steam pipeline include, among other things, variable values of the coefficient of heat transfer between the pipeline material and the medium flowing inside it, which, at this stage of boiler operation, may change its state. Unsteady operation of a pipeline, especially in case of subsequent boiler start-ups, may induce thermal stresses which exceed the values of allowable stress in components of complex shapes. Research limitations/implications: The possibility of applying the durability criteria currently assumed in standards still requires justification and confirmation in laboratory and industrial conditions to be closer to the real components behaviour. In such situation the presented analysis is the part of the complex investigation method which main purpose is increasing accuracy of the TMF process description and thermo-mechanical life assessment. Practical implications: The calculations carried out may constitute a basis for developing a material test parameters which would bring closer the fatigue conditions appearing locally in the analysed components. The method of stress-strain behaviour analysis used in the paper could be useful in the practical cases when the real components mechanical behaviour would be analysed. Originality/value: The main value of this paper is the own method of the mechanical behaviour analysis of the power plant component. This method includes the temperature fields analysis taking into account the boundary conditions based on the operation parameter data and the thermoplastic material model. The material stress-strain behaviour has been treated as the local phenomenon, that could be modelled by FEM.
Rocznik
Strony
71--78
Opis fizyczny
Bibliogr. 20 poz., rys., tabl.
Twórcy
autor
autor
  • Department of Material’s Technology, Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice, Poland, jerzy.okrajni@polsl.pl
Bibliografia
  • [1] BS 7910, Guide on methods for assessing the acceptability of flows in structures (replacing PD 6493 and PD 6539), British Standards Institution, London, 1994.
  • [2] Nuclear Electric Ltd: Assessment Procedure for the High Temperature Response of Structure. Proc, R5/2, UK, 1997.
  • [3] S. Webster, A. Bannister, Structural Integrity Assessment Procedure for Europe - of the SINTAP programme overview, Engineering Fracture Mechanics 67/6 (2000) 481-514.
  • [4] Project European Thematic Network FITNET FFS-GIRT-CT-2001-05071.
  • [5] J. Bressers. L. Remy (eds.), Fatigue under Thermal and Mechanical loading, Kluwer Academic Publishers, Netherlands, 1996.
  • [6] P. Hähner et al, Research and development into a European code-of-practice for strain-controlled thermo-mechanical fatigue testing, International Journal of Fatigue 30/2 (2008) 372-381.
  • [7] H. Sehitoglu, Thermal and Thermo-mechanical Fatigue of Structural Alloys, Fatigue and Fracture 19 (1996) 527-556.
  • [8] S. S. Manson, Thermal Stress and Low Cycle Fatigue, McGraw-Hill, New York, 1966.
  • [9] J. Okrajni, K. Mutwil, M. Cieśla, Steam pipelines’ effort and durability, Journal of Achievements in Materials and Manufacturing Engineering 22/2 (2007) 63-66.
  • [10] D. Renowicz, A. Hernas, M. Cieśla, K. Mutwil, Degradation of the cast steel parts working in power plant pipelines, Proceedings of the 15th Scientific International Conference „Achievements in Mechanical and Materials Engineering” AMME’2006, Gliwice-Wisła, 2006, 219-222.
  • [11] Z. Orłoś, Thermal stresses, PWN, Warsaw, 1991 (in Polish).
  • [12] Standards EN 12952-3:2001 (E), EN 12952-4:2000.
  • [13] I. J. Perrin, J. D. Fishburn, A Perspective on the Design of High Temperature Boiler Components, Proceedings of the Conference Creep and Fracture in High Temperature Components, London 2005, DEStech Publications, Inc., Lancaster, Pennsylvania 17601 USA.
  • [14] J. Okrajni, The durability of power plant pressure vessels from the point of view of obligatory standards, Power Engineering 18 (2008) 93-100 (in Polish).
  • [15] J. Okrajni, Thermo-mechanical conditions of power plant components, Journal of Achievements in Materials and Manufacturing Engineering 33/1 (2009) 53-61.
  • [16] J. Okrajni, G. Junak, A. Marek, Modelling of the deformation process under thermo-mechanical fatigue conditions, International Journal of Fatigue 30/2 (2008) 324-329.
  • [17] J. Okrajni, A. Marek, G. Junak, Description of the deformation process under thermo-mechanical fatigue, Journal of Achievements in Materials and Manufacturing Engineering 21/2 (2007) 15-24.
  • [18] D. Renowicz, M. Cieśla, Crack initiation in steels parts working in boilers and steam pipelines, Journal of Achievements in Materials and Manufacturing Engineering 21/2 (2007) 49-52.
  • [19] J. Dobrzański, The classification method and the technical condition evaluation of the critical elements’ material of power boilers in creep service made from the 12Cr-1Mo-V, Journal of Materials Processing Technology 164/165 (2005) 785-794.
  • [20] A. Neimitz, I. Dzioba, M. Graba, J. Okrajni, The assessment of the strength and safety of the operation high temperature components containing crack, Kielce University of Technology Publishing House, Kielce, 2008.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BOS2-0022-0039
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