Evaluation of Numerical Methods to Predict Temperature Distributions of an Experimentally Investigated Convection-Cooled Gas-Turbine Blade

Abstract

This paper presents two different numerical methods to predict the thermal load of a convection-cooled gas-turbine blade under realistic operating temperature conditions. The subject of the investigation is a gas-turbine rotor blade equipped with an academic convection-cooling system and investigated at a cascade test-rig. It consists of three cooling channels, which are connected outside the blade, so allowing cooling air temperature measurements. Both methods use FE models to obtain the temperature distribution of the solid blade. The difference between these methods lies in the generation of the heat transfer coefficients along the cooling channel walls which serve as a boundary condition for the FE model. One method, referred to as the FEM1D method, uses empirical one-dimensional correlations known from the available literature. The other method, the FEM2D method, uses three-dimensional CFD simulations to obtain two-dimensional heat transfer coefficient distributions. The numerical results are compared to each other as well as to experimental data, so that the benefits and limitations of each method can be shown and validated. Overall, this paper provides an evaluation of the different methods which are used to predict temperature distributions in convection-cooled gas-turbines with regard to accuracy, numerical cost and the limitations of each method. The temperature profiles obtained in all methods generally show good agreement with the experiments. However, the more detailed methods produce more accurate results by causing higher numerical costs.

Surface Temperature Measurements in an Industrial Gas Turbine Using Thermal History Paints

“…The material temperature of the blade is predicted using the so called FEM2D method (Findeisen et al, 2017). The heat transfer coefficient is obtained by a CFD simulation of the main flow as well as the cooling air.…”

Surface temperature condition monitoring methods for aerospace turbomachinery: exploring the use of ultrasonic guided waves

“…Coupled methods use computational fluid dynamic (CFD) calculations to iterate the heat transfer coefficients, which improves accuracy over uncoupled methods. Findeisen et al [17] compared two coupled methods, FEM1D and FEM2D. The FEM1D method uses simplified models of the cooling system making it suitable for initial designs, while the FEM2D method uses three dimensional CFD simulations that are more realistic but nearly a hundred times slower than FEM1D.…”