PREDICTION OF NOX PRODUCTION IN A TURBULENT HYDROGEN-AIR JET FLAME

A major concern in the numerical study of turbulent nonpremixed flames is the accurate prediction of trace species. The production of pollutants such as NOx during unsteady combustion needs to be understood and predicted accurately so that the design of the next generation's combustion systems can meet the forthcoming stricter environmental restrictions. Numerical studies using steady-state methods cannot account for the unsteady phenomena in the mixing region, and therefore, fail to accurately predict the NOx production that could occur. A novel unsteady mixing model is demonstrated here that accounts for all the length scales associated with mixing and molecular diffusion processes. Finite-rate kinetics in the form of a reduced mechanism have been used to study hydrogen-air nonpremixed jet flames. NOx production in these jet names was also predicted. Comparisons with experimental data and pdf calculations show good agreement, thereby, providing validation or the mixing model.