Numerical Simulation On Two-dimensional Slit Flame Of Oxygen Diluted Partially Premixed/oxygen Enriched Supplemental Combustion

The principle of oxygen diluted partially premixed/oxygen enriched supplemental combustion is: hydrocarbon fuel and oxidant premixed in same equivalence ratio flow into the combustion chamber, and then form a power flame. Then the oxygen enriched react with the uncompleted burned fuel and the reduced product,which forms diffusion flame. By adjusting the oxygen concentration and equivalence ratio of partially premixed, we can adjust the concentration distribution of fuel/ oxidant in power combustion zone, in order to reduce the chemical reaction rate, thicken the surface of dynamic flame, balance temperature of reaction zone, control the emissions of NOx in main combustion zone.This paper has established a geometric model which is the same as the experimental model. The numerical simulation for multi engineering conditions of different equivalence ratio of the overall, different equivalence ratio of partially premixed, and different oxygen diluted concentration conditions were accomplished. This article analyses the effects of two-dimensional oxygen concentration distribution on flame structure, reaction mechanism and pollutant emissions, and compared numerical simulation results with the experimental results. The study found that, the flame structure and emission regulation of the simulation results is the same as laboratory results, which implies that numerical simulation method is feasible. Oxygen diluted partially premixed/oxygen enriched supplemental combustion is very effective to improve combustion efficiency and reduce pollutant emissions.A comparative analysis is done on the following conditions which include equivalence ratio of the overall Φt=0.65, 0.7, 0.8, 0.9, equivalence ratio of partially premixed Φp=1.2, 1.3, 1.4 and the oxygen diluted concentration α=17%,18%,19% and 20%. Results show that the optimum operating condition is: Φt=0.8 for the equivalence ratio of the overall, ΦP=1.3-1.4 for the equivalence ratio of the partially premixed flow and α=18% for the oxygen diluted concentration.