Study on numerical methods for conjugate heat transfer simulation of an air cooling turbine

The effects of several numerical methods, including computational grids, coupling method, transition model and inner cooling air flow prediction, on the conjugate simulations were studied in the research. Firstly a finite difference conjugate solver was developed. Such solver included an N-S solver and a thermal conduction module for fluid flow and solid thermal conduction, respectively. Then conjugate simulations of an air cooling turbine were carried out. There were four kinds of conjugate simulations: the first one employs different types of computational grids, including H-type grids and O-type grids, for discretizing near-wall regions in fluid zone; the second one employs different coupling methods including indirect and direct ones; the third one employs different models including the B-L and q-ω turbulence models, and the AGS transition model; and the forth one employs different turbulence models for the prediction of flows in the cooling channels. All of the numerical results have been compared to the experimental result. Finally it concludes that to accurately predict thermal and aerodynamic load of the air cooled turbine, the conjugate simulation should employ O-type girds to discretize the near wall regions in the fluid zone, use the direct coupling method to transfer data between solid and fluid domains, and utilize the transition model to predict accurate flow details within the boundary layers, and also account for flows in the cooling air channels.