Effects of Fuel-Side Nitrogen Dilution on Structure and NO_x Formation of Turbulent Syngas Non-premixed Jet Flames

摘要

In the present study, we have numerically investigated the effects of the fuel-side nitrogen dilution on the precise structure and NO_x, formation characteristics of the turbulent syngas non-premixed flames. The turbulence-chemistry interaction is represented by the Lagrangian flamelet model. In context with the Lagrangian flamelet model, the NO concentration is obtained directly from the flamelet calculation based on the full NO_x. chemistry, and the radiative heat loss is taken into account through the flamelet energy equation. Computations are made for three fuel-side nitrogen-diluted syngas non-premised flames. Numerical results indicate that, for the highly nitrogen-diluted case with the higher scalar dissipate rate and the shorter flight time, the Same structure is dominantly influenced by the turbulence-chemistry interaction and marginally modified by the radiation effect. On the other hand, the flame structure for the no-dilution case with the longer flight time and the relatively intermediate scalar dissipate rate is influenced strongly by the radiative cooling, as well as moderately by the turbulence-chemistry interaction. Numerical results suggest that the NO_x formation in the syngas turbulent non-premised flames can be effectively suppressed by increasing the 'fuel-side nitrogen dilution level.