In order to contribute to the life assessment of the first stage rotor blade, transient analyses of heat transfer in the start-up and shut-down of a power generation gas turbine (GT) were conducted by thermal conjugation inside and outside the blade, which consist of thermal convection and heat conduction. Characteristic diagrams in a hot start and a normal shut-down that simulate an actual plant were used to set the numerical conditions.
The characteristics of the predicted blade temperature distributions were classified into two regions for load and no-load operation. In the no-load operation in which conduction heat transfer was dominant, the temperatures of the leading and the trailing edges changed drastically and the gradient of the temperature on the blade root increased substantially after ignition. In the load operation, the configuration of the blade temperature profile remained similar over half load.
It was possible to use the predictions to estimate stress and creep strain, which are demanded for the life assessment of the blade, from the start-up to the shut-down.