Transient heat transfer as a leading factor in fatigue of thick-walled elements at power plants

The authors present a numerical study of a start-up of a boiler with a thick-walled element subjected to thermomechanical loading. The significance of calculations of real heat transfer coefficients has been demon-strated. Fluid dynamics, mechanical transient thermal and static structural calculations have been conducted in both separate and coupled modes. Strain-stress analyses prove that the effect of the heat transfer coefficient changing in time and place in comparison with a constant one as recom-mended by standards is the key factor of fatigue calculations.