Experimental and numerical investigation of jet impingement cooling onto a concave leading edge of a generic gas turbine blade

Abstract

This study focuses on an experimental and numerical heat transfer investigation of an impingement jet array with a concave target plate that resembles a turbine blade's leading edge. The array consists of nine circular jets with a diameter of Djet and the target plate has a curvature radius of R=Djet. The target plate also features film cooling holes in a staggered configuration so that each jet is surrounded by three film cooling holes. A Reynolds number of 30,000 is tested, while the separation distance H is altered between H/Djet=2.7 and H/Djet=4. In addition the jets are exposed to a crossflow (cf). The experimental heat transfer data are obtained by using the transient Thermochromic Liquid Crystal (TLC) method. In the Computational Fluid Dynamics (CFD) study 3D steady state Reynolds-Averaged Navier-Stokes (RANS) simulations with the software package OpenFOAM and the kω−shear−stress−transport (SST) turbulence model are performed. The numerical results from OpenFOAM agree well with the experimental data and local flow phenomena are captured correctly. The crossflow decreases the stagnation point heat transfer as well as the overall heat transfer but homogenizes the local heat transfer distribution. A smaller separation distance enhances the crossflow effects and generally increases the heat transfer level.