采用详细化学反应机理的火焰面模型模拟煤油两相燃烧流场

Flamelet modeling of two-phase kerosene combustion flow fields using a detailed chemical reaction mechanism

基于可实现的k-ε湍流模型、颗粒随机轨道模型、火焰面模型和航空煤油详细化学反应机理对模型燃烧室内两相燃烧流场进行了数值模拟.其中详细反应机理由替代燃油(80%质量分数的正癸烷,20%质量分数的1,2,4-三甲基苯)的反应机理和NOx的反应机理组合而成.通过与实验数据的比较,考察采用该详细化学反应机理的火焰面模型模拟RP-3航空煤油燃烧流场的准确性,特别是污染物排放计算的精度.结果表明:稳态火焰面模型模拟的温度场和CO2生成量与实验数据吻合较好,而预测的NO排放量与实验值偏差较大;非稳态火焰面模型显著提高了NO的预测精度,在工况1(来流马赫数为0.16,进口温度为537 K,油气比为0.004 8,常压)条件下与实验数据吻合较好,但在工况2(来流马赫数为0.155,进口温度为523 K,油气比为0.010,常压)条件下仍过高估计了NO的排放量.

Two-phase combustion flow fields in a model combustor were numerically simulated using realizable k-ε turbulent model,particles stochastic trajectory model,flamelet models and the detailed chemical reaction mechanism of aviation kerosene.The detailed reaction mechanism was assembled using the combustion mechanism of surrogate fuel（80% decane and 20% 1,2,4-trimethylbenzene by mass fraction） and NOx formation mechanism.The accuracy of flamelet modeling of RP-3 kerosene combustion flow fields（especially for NO emissions） employing the detailed reaction mechanism was investigated by comparison with the experimental data.The result shows that the temperature and CO2 concentrations predicted using the steady flamelet model are in good agreement with the experimental data,but the NO emissions have a bigger deviation.The use of unsteady flamelet model significantly improves the prediction accuracy of NO concentrations and shows good agreement with the experimental data in condition 1（inlet Mach number 0.16,inlet temperature 537K,fuel-air ratio 0.0048,atmospheric pressure）,but NO emissions are overpredicted in condition 2（inlet Mach number 0.155,inlet temperature 523K,fuel-air ratio 0.010,atmospheric pressure）.