The Study of Effects of Additives on the NOx Formation in $H_{2}/O_{2}/N_{2}$ Premixed Flames with Oxygen Enrichments

산소부화된 $H_{2}/O_{2}/N_{2}$ 예혼합 화염에서 첨가제가 NOx 생성에 미치는 영향 연구

Numerical simulations are performed at atmospheric pressure in order to understand the effect of additives on flame speed and the NOx formation in freely propagating $H_{2}/O_{2}/N_{2}$ flames with oxygen enrichments. A chemical kinetic mechanism is developed, which involves 26 gas-phase species and 99 reactions. Under several equivalence ratios and oxygen enrichments, flame speeds are calculated and compared with those obtained from the experiments, the results of which is in good agreement. As hydrogen chloride as additive is added into $H_{2}/O_{2}/N_{2}$ flames with low oxygen enrichments, its chemical effect causes the decrease of flame speed, radical concentration, and the NO production rate. It is found that the chemical effect of additive has much more influence on the reduction of EINO than its physical effect. However, in flames with very high flame temperature the physical effect rather than the chemical effect becomes more important on the reduction of EINO.