Thermal Conjugate Analysis of a First Stage Blade in a Gas Turbine

Three-dimensional numerical analyses of heat transfer were conducted by thermal conjugation of the inside and outside fields of a first stage rotor blade in a gas turbine, which consists of convection heat transfer and thermal conduction. The target of the analysis was a blade with multiple cooling holes. In order to make an accurate estimation of the blade temperature, the heat exchange in cooling passages, the outflow of cooling air and the effect of rotation were taken into account by the numerical method. The predicted distribution of surface temperature was in good agreement with the observed surface pattern on an actual blade. In addition case studies for bucket temperature were carried out using the present numerical method. It was shown that the temperature field inside the blade was severely influenced by the assumed distribution of inlet gas temperature and cooling air flow conditions. As a result, it is clear that the present analytical method is useful for prediction of blade temperature depending on various conditions in operation.