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基于扩展甲醇氧化机理,数值分析了不同氮气稀释比下的甲醇-空气-稀释气的层流预混燃烧特性和火焰结构特性.获得了甲醇-空气-稀释气的层流燃烧速度、质量燃烧流量、绝热火焰温度、全局活化温度、泽多维奇数和有效路易斯数等燃烧特性参数以及层流预混火焰结构信息.研究表明,扩展甲醇氧化机理适用于计算稀燃和化学计量比附近甲醇-空气-稀释气层流预混火焰特性和燃烧化学反应过程.层流燃烧速度和质量燃烧流量随氮气稀释比的增加而减小,且在混合气较稀时受稀释气的影响更明显.混合气有效路易斯数随稀释比的增加而略有增加,火焰锋面热扩散不稳定性被抑制.热膨胀比随稀释比的增加而降低,火焰厚度随稀释比的增加而增加,稀释气的加入抑制了火焰锋面的流体力学不稳定性.稀释气添加导致的反应物浓度下降和火焰温度下降影响了甲醇燃烧火焰结构,降低了甲醛和NOx浓度.
Based on the extended methanol oxidation mechanism, the laminar flow premixed combustion characteristics and flame structure characteristics of methanol-air-diluent gas were numerically analyzed, and the laminar flow velocity, mass flow rate , The adiabatic flame temperature, the global activation temperature, the Zerodowicz number and the effective Lewis number, as well as the information of the laminar pre-mixed flame structure.The results show that the extended methanol oxidation mechanism is suitable for the calculation of the methanol-air- The characteristics of premixed flame and the reaction process of chemical reaction during the combustion process are also discussed.The laminar flow velocity and mass flow rate decrease with the increase of nitrogen dilution ratio and are more affected by the diluent gas when the mixture is lean. The Lewis number increased slightly with the increase of dilution ratio, and the thermal diffusion instability of flame front was inhibited.The thermal expansion ratio decreased with the increase of dilution ratio, and the flame thickness increased with the increase of dilution ratio. The addition of diluent gas inhibited the flame front Of the hydrodynamic instability.Dilution of gas caused by the reactant concentration decreased and the flame temperature drop affected the combustion of methanol flame Configuration, and reduce the NOx concentration of formaldehyde.