Nox Production Mechanism Simplified Method Research And Analysis With Pulse Combustion Based On Gri-Mech3.0

With the increasingly high proportion in energy consumption, natural gas and its NOx emissions during combustion process gradually become the focal point of various researches. In the methods of reducing NOx emissions from natural gas combustion, low NOx emissions technologies are popular because its less costs. Among them, pulse combustion becomes one of the higher combustion efficiency and lower pollution emissions technologies.By the previous experiment results of our work group, NOx emissions from pulse combustion have minimum point when the equivalence ratio was four. So the influence mechanism of low NOx emissions in partially premixed flames from pulse combustion with the equivalence ratio of four was studied in this work. The NOx production mechanism on the flame surface of methane pulse combustion was discussed, the detailed mechanism of methane pulse combustion chemical kinetics (GRI-Mech3.0) was reduced, and a laminar flamelet model was proposed combined with reduced chemical kinetics to study the low NOx emission mechanism. The main work and results are as follows:1. The opposed flow flame model was used to discuss the NOx production mechanism on the flame surface of methane pulse combustion by sensitivity analysis method. It was concluded that NO component of pulse combustion flame surface was explained by the dominant mechanism about prompt and thermal NOx, and the prompt NOx mechanism affect the whole flame region, while the thermal NOx mechanism affect the external flame region.2. Based on the results of sensitivity analysis and production rate anslysis, the detailed mechanism of methane pulse combustion chemical kinetics (GRI-Mech3.0) was reduced, and the accuracy and applicability of the reduced mechanism was proved.3. A laminar flamelet model combined with flamelet database constructed by reduced mechanism for pulse combustion was proposed to simulate stable combustion and pulse combustion, the computed results were with great agreement to the experimental data. By analyzing the distribution of temperature, NO and intermediate product, it was concluded that the reasons of low NOx emission in pulse combustion were the shorter residence time of reactant in high temperature region, as well as the strong mixing of fuel and air by sound affect.