To accurately predict the turbulent flow and convective heat transfer of impingement jet cooling, widely used in engine hot-section components, this study proposes a new hybrid Very Large Eddy Simulation (VLES) method. This method combines the WALE and Smagorinsky subgrid-scale models to improve predictions of near-wall convective heat transfer and shear flow in free turbulent regions. Three-dimensional unsteady high-fidelity numerical simulations were performed for a typical flow and heat transfer problem: single-hole and triple-hole impinging jets at Reynolds number (Re) = 40,000 and a jet-to-plate distance of 6. The numerical predictions of three Reynolds-Averaged Navier-Stokes (RANS) methods – Realizable k-ε, SST k-ω, and Transition SST – were compared with those of the newly developed VLES method. The results show that the newly developed VLES method can capture the evolution and development of large-scale and small-scale vortex structures during the impingement process, including those in the free jet region and the wall jet region. Furthermore, the predictions of the Nusselt number (Nu) on the impingement target surface show good agreement with experimental data. In contrast, the RANS methods over-predicted convective heat transfer at the impingement target surface. This demonstrates that the newly developed VLES method can accurately predict flow and heat transfer problems associated with impinging jets.

Flow and heat transfer, Hybrid Very Large Eddy Simulation, Impinging jets