Assessing the effect of thermal transients on the life of boiler plant

Currently difficulties exist for the design engineer confronted with the design or assessment of conventional steam power plant boiler components which operate in a creep-fatigue environment. These arise from the ultra-conservative methods available and the paucity of data describing the creep-fatigue interaction mechanism. The author describes how Babcock have utilised a hybrid method to analyse the creep-fatigue life of boiler components. The method is believed to provide sufficient conservatism while still maintaining economically designed components. Use of the finite element method for thermal and stress analysis aids in the correlation between operational events and damage mechanisms. A novel method of online monitoring of thermal fatigue has been developed based on finite element analysis