Comparison Between Unstructured and Structured Meshes With Different Turbulence Models for a High Pressure Turbine Application

Abstract

For the CFD community the mesh generation is still one of the most important stages to obtain a good flow solution based on the full Navier-Stokes equations. For turbomachinery blade passages this task is not straightforward mainly due to the 3D domain and the complex geometries involved. The mesh quality and and elements distribution, orthogonality, smoothing, aspect ratio and angles are very important to guarantee a good numerical stability and solution accuracy. Moreover, the structure of the mesh inside the boundary-layer should be built carefully mainly in the regions where there are horseshoe vortices and tip leakage flow. In this work, the 3D turbulent flow is calculated and compared for structured and unstructured meshes including two equation models and Reynolds stress models. A high pressure turbine with 4.0 total-to-total pressure ratio is used in this study. A commercial software is used for mesh generation and flow calculation. The results are presented comparing the pressure ratio and efficiency from numerical solutions and experimental data and flow properties distributions along the blade span.