MULTIDIMENSIONAL-ANALYSIS OF TURBULENT NATURAL-GAS FLAMES USING DETAILED CHEMICAL-KINETICS

A numerical approach for predicting multi-dimensional reacting flows i s presented. The various interacting processes which occur during comb ustion are considered: turbulent transport, chemical reaction, and rad iative heat transfer. The formulation is based on time-averaged transp ort equations. Turbulent transport is modeled with the k-epsilon turbu lence model, chemical reactions are considered using the eddy dissipat ion concept (EDC), and radiative heat transfer is modeled with the dis crete ordinates method. The EDC includes influences of both local turb ulence and finite-rate chemical kinetics on the reaction rates, and is applicable to general, n-step, elementary reaction mechanisms. The mo del is applied to two swirling natural gas flames. Predictions are pre sented for several detailed and reduced reaction mechanisms including the 279-step GRI-Mech. Results indicate that the use of intermediate a nd detailed reaction mechanisms with the EDC significantly reduces unc ertainty associated with simple one- and two-step chemistry, but also that k-epsilon model underpredicts turbulent transport in the consider ed flames.