Thermal stress monitoring in thick-walled pressure components based on the solutions of the inverse heat conduction problems

Thick-walled components of the thermal power unit limit the maximum heating and cooling rates during startup or shutdown of the unit. A method of monitoring the thermal stresses in thick-walled components of thermal power plants is presented. The time variations of the local heat transfer coefficient on the inner surface of the pressure component are determined based on the measurement of the wall temperature at one or six points, respectively, for one- and three-dimensional unsteady temperature fields in the component. The temperature sensors are located close to the internal surface of the component. A technique for measuring the fast-changing fluid temperature was developed. Thermal stresses in pressure components with complicated shapes can be computed using finite element method (FEM) based on experimentally estimated fluid temperature and heat transfer coefficient.