Résumé | A numerical study of soot formation and NOx emission in axisymmetric coflow laminar methane/hydrogen-air diffusion flame was conducted using detailed gas-phase chemistry and complex thermal and transport properties. To investigate the impact of hydrogen addition, three cases were studied, namely, Case 1, maintaining a constant volume flow of fuel. Case 2, maintaining the fuel heat release rate unchanged, and the fuel nozzle diameter unchanged. Case 3, maintain the fuel heat release rate unchanged, and the fuel jet velocity constant. The results show that, in all three cases, with increasing level of H 2 addition, the flame height decreased, the reaction zone length shortened, residence time shortened, therefore, soot surface growth was inhibited, soot formation reduced, and NO x emissions reduced. Effects of hydrogen addition on soot formation and NO x emissions in Case 2 and Case 3 were much worse than that in Case 1. The results also show that while in reducing soot formation and NO x emission, effect of hydrogen addition in Case 3 was better than that in Case 2. |
---|