Efficient Modelling of Blade Cooling Using a Hybrid 1D-3D Approach

Abstract The first turbine stages downstream of the combustor are subjected to extreme high temperatures. Simulating the flow and heat transfer in and around the blades is therefore crucial for optimizing cooling and achieving the highest possible engine efficiencies. The blade cooling optimization process requires iteration on many parameters. Due to the disparity in the geometrical length scale between the blade itself, the internal cooling channel structures, and the cooling holes, meshing and solving the cooling flow inside a turbine blade using a full 3D CFD model is very time-consuming and costly. 1D CFD codes allow for detailed and efficient modelling of the internal cooling flow in the conceptual design stage. The effort involved and the computational cost are orders of magnitude less than for a fully resolved 3D internal flow CFD simulation. In contrast, the main passage flow simulation is still well suited to a 3D CFD model. The current work describes the coupling of a 1D flow and heat transfer network model to account for the internal cooling structures with a 3D CFD model for the main passage flow on a typical gas turbine vane geometry. The so-called injection region model was used to model the film cooling flow injection at the vane surface without having to resolve each hole patch by the surface mesh itself. The paper presents a validation of the injection region model, and it compares the results of the different modelling approaches, including the hybrid 1D-3D model. The 1D network model is able to predict accurate film cooling inflow conditions for the 3D CFD simulation. The results of the injection region model show good agreement with that of the fully resolved 3D simulation. Therefore, it has the potential to speed-up the film cooling simulations in the early design phase.