Local turbulent convective heat transfer from a flat plate to a circular impinging air jet is numerically investigated. The jet-to-plate distance (L/D) effect on local heat transfer is the main focus of this study. The eddy viscosity V2F turbulence model is used with a nonuniform structured mesh. Reynolds-Averaged Navier-Stokes equations (RANS) and the energy equation are solved for axisymmetric, three-dimensional flow. The numerical solutions obtained are compared with published experimental data. Four jet-to-plate distances, (L/D = 2, 4, 6 and 10) and seven Reynolds numbers (Re = 7,000, 15,000, 23,000, 50,000, 70,000, 100,000 and 120,000) were parametrically studied. Local and average heat transfer results are analyzed and correlated with Reynolds number and the jet-to-plate distance. Results show that the numerical solutions matched experimental data best at low jet-to-plate distances and lower Reynolds numbers, decreasing in ability to accurately predict the heat transfer as jet-to-plate distance and Reynolds number was increased.

Local turbulent convection heat transfer from a flat plate to a circular impinging air jet is investigated numerically, with emphases on the effect of inlet flow condition, i.e. velocity profiles, on the impingement jet heat transfer distribution on a flat plate. Reynolds-Averaged Navier-Stokes equations (RANS) and the energy equation are solved for axisymmetric, three-dimensional flow. Eddy viscosity k-ε (RNG) and V2F turbulence models are used with non-uniform meshes to obtain mesh-independent solutions. Three Reynolds numbers, i.e. 23,000, 50,000 and 75,000 and three geometries (jet-to-plate distance, L/D = 2, 4, & 6), and four inlet velocity profiles are used in the analysis. The numerical solutions obtained are compared with existing experimental heat transfer data. The results show that stagnation region heat transfer is most sensitive to inlet velocity profiles at small jet-to-plate distances. The Blasius and long pipe (P/D = 20) profiles have the best match with experimental data in the secondary heat transfer maximum region (r/D = 2). As Reynolds number increases, it’s very difficult to predict heat transfer in the region of secondary maximum, where flow transition takes place.