Thermal conjugate analysis of a first stage gas turbine blade

Abstract

Three-dimensional numerical analysis of heat transfer was conducted by thermal conjugate fields inside and outside a blade, which consist of convection heat transfer and thermal conduction. The target of the analysis was a 1 st-stage blade of gas turbine with multiple cooling holes. In order to make an accurate estimation of the blade temperature, heat exchange in cooling passages, outflow of cooling air and effect of rotation were taken into account by the numerical method. Predicted distribution of surface temperature was in good agreement with the observed surface pattern on an actual blade. Also case studies for blade temperature were carried out using the present numerical method. It was shown that a 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 depended on various conditions in operation.