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Abstract: Demand for greater engine efficiency and thrust-to-weight ratio has driven the production of aircraft engines with higher core temperatures and pressures. Such engines operate at higher fuel–air ratios, resulting in the potential for significant heat release and chemical reactions on a film-cooled surface. Currently, there is little basis for understanding the effects on aero-performance and durability due to such secondary reactions. In this paper, the chemically reactive turbulent film cooling over a surface for three cases of an inclined single and two parallel and compound-angle coolant holes is investigated by a Reynolds-averaged Navier–Stokes approach with the shear-stress transport (SST) turbulence model using OpenFoam. To take into account the secondary combustion resulting from the unburned fuels in the crossflow, a two-step reaction scheme was used for the combustion of propane. The relative increase in surface heat flux due to near wall reactions was investigated for film cooling with N2 and air injections. An eddy dissipation concept fast chemistry approach was used to account for the turbulence–chemistry interaction. Results demonstrate that reactions in the turbine cooling film can result in increased heat transferred to the surface. Failure to design for this effect could result in augmented heat transfer caused by the cooling scheme, and turbine life could be degraded substantially. The analysis suggests that high fuel–air ratio designs may have to consider changes to cooling strategies to accommodate secondary combustion. [Copyright &y& Elsevier]

Abstract: Non-premixed turbulent reacting flow in a methane-fuelled coaxial jet combustor has been studied numerically employing Reynolds Averaged Navier–Stokes (RANS) models. A local extinction approach for treating chemical reaction kinetics within the eddy dissipation concept (EDC) has been examined. It applies a database of pre-calculated chemical time scales, which contains the influence of chemical kinetics that is otherwise time-consuming to calculate. Simulations were carried out using standard k-epsilon, RNG k-epsilon and k-Omega SST turbulence models by open-source CFD-toolbox OpenFOAM. The results were compared to available numerical results and experimental data for predicting velocity, and temperature fields. All simulations were conducted with a reasonable number of meshes to demonstrate the accuracy of different turbulent RANS models in OpenFOAM solver which has a wide range of engineering applications in such type of flows. [Copyright &y& Elsevier]