Active-grid turbulence effect on the topology and the flame location of a lean premixed combustion

Abstract

Lean premixed combustion under the influence of active-grid turbulence was computationally investigated, and the results were compared with experimental data. The experiments were carried out to generate a premixed flame at a thermal load of 9 kW from a single jet flow combustor. Turbulent combustion models, such as the coherent flame model (CFM) and turbulent flame speed closure (TFC) model were implemented for the simulations performed under different turbulent flow conditions, which were specified by the Reynolds number based on Taylor’s microscale (Reλ), the dissipation rate of turbulence (ε) and turbulent kinetic energy (k). This study shows that the applied turbulent combustion models differently predict the flame topology and location. However, similar to the experiments, simulations with both models revealed that the flame moves toward the inlet when turbulence becomes strong at the inlet, that is, when Reλ at the inlet increases. The results indicated that the flame topology and location in the coherent flame model were more sensitive to turbulence than those in the turbulent flame speed closure model. The flame location behavior on the jet flow combustor significantly changed with the increase of Reλ.