Issues of film cooling simulation by CFD methods

This paper is devoted to the issue of film cooling modeling of high-temperature turbine blades. In cases when air is injected onto the outer surface of the blade, thermal calculation software based on empirical data does not take into account the air movement direction. This can be critical when cooling holes are made towards each other and counter-directed flows are formed in the middle section of the blade. To assess such a flow, it is necessary to solve the conjugate thermal-hydraulic simulation in a complete statement, which can be done using commercial packages, for example, Ansys CFX. This work contains a study of the influence of the grid and numerical model parameters on the turbine blade thermal state in direct modeling of the conjugate thermal-hydraulic simulation. In this paper, the influence of grid parameters and solver settings was preliminarily investigated using a flat plate as an example. The results of the simulation and experimental data comparison showed a strong dependence on the grid parameters and the absence of grid convergence. The calculated values approach the experimental ones only at a large distance from the cooling hole. Similar results were shown by the computational and experimental study of vane film cooling. The film on the vane surface strongly depends on the grid discretization and solver settings. Using the recommended grid and solver settings for the convective heat transfer simulations leads to the presence of an excessively intense film along the entire vane, which contradicts the experimental data. The issue of numerical modeling of the film cooling vanes remains relevant.