Creep-fatigue interaction effects on pressure-reducing valve under cyclic thermo-mechanical loadings using direct cyclic method

Nak-Kyun Cho, Youngjae Choi, Haofeng Chen

Research output: Contribution to journalArticlepeer-review

Abstract

Supercritical boiler system has been widely used to increase efficiency of electricity generation in power plant industries. However, the supercritical operating condition can seriously affect structural integrity of power plant components due to high temperature that causes degradation of material properties. Pressure reducing valve is an important component being employed within a main steam line of the supercritical boiler, which occasionally thermal-fatigue failure being reported. This research has investigated creep-cyclic plastic behavior of the pressure reducing valve under combined thermomechanical loading using a direct numerical method known as extended direct steady cycle analysis of the linear matching method framework (LMM eDSCA). Finite element model of the pressure-reducing valve is created based on a practical valve dimension and temperature-dependent material properties are applied for the numerical analysis. The simulation results demonstrate a critical loading component that attributes creep-fatigue failure of the valve. Parametric studies confirm the effects of magnitude of the critical loading component on creep deformation and total deformation per loading cycle. With these comprehensive numerical results, this research provides engineer with an insight into possible failure mechanisms of the pressure-reducing valve at high temperature.

Original languageEnglish
Article number011507
JournalJournal of Pressure Vessel Technology
Volume144
Issue number1
Early online date7 Oct 2021
DOIs
Publication statusPublished - 1 Feb 2022

Keywords

  • pressure reducing valve
  • creep
  • cyclic plasticity
  • linear matching method
  • supercritical boiler

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