Numerical Analysis of the Multiple-Horseshoe-Vortex Effects on the Endwall Heat Transfer in the Leading-Edge Region of a Symmetric Bluff Body

The present contribution covers results of a CFD analysis of the 3D flow and endwall heat transfer for a generic junction configuration with a wall-mounted symmetric bluff body experimentally investigated by Praisner and Smith [1, 2]. The computations based on the Reynolds-averaged Navier-Stokes equations (RANS) were performed using two codes of second order accuracy: the in-house code SINF and the commercial package ANSYS-CFX 12.0. For the turbulence closure problem, the Menter SST turbulence model with and without the streamline-curvature correction term was used. The grid sensitivity of solution was studied using a set of grids, the finest of which was of about five million cells. In accordance with the experiments, the computations with both the codes predict development of multiple horseshoe vortices and several bands of high values of the Stanton (St) number upstream of the body leading edge. The spatial relationships between the vorticity in individual planes and the associated endwall Stanton number are generally same in the measurements and in the computations. Some quantitative distinctions between the predictions and experimental data are attributed to the smoothing effect of the low-frequency unsteadiness of the horseshoe vortex system developing in the real flow. Simulation of this effect is outside of RANS-based formulations.