中文摘要：

本文对甲烷和空气在突扩燃烧室内的预混燃烧进行了大涡模拟（LES）研究,主要关注于预混燃料的湍流强度对甲烷-空气预混燃烧效率的影响.LES数值模拟给出了不同入口湍流强度的条件下燃烧室内湍流预混燃烧反应流场的速度场,温度场和浓度场分布.分析的结果表明：随着预混燃料入口湍流强度的增大,燃烧反应更加剧烈,燃烧效率提高,火焰长度也随之变短,同时,一氧化碳的生成区域明显变小,整体生成量减少.研究的结果对有效地提高燃气轮机的燃烧效率和减少污染物的排放提供一定的参考依据.

英文摘要：

Premixed combustion of methane and air in the combustion chamber with a sudden enlargement was simulated numerically by using Large Eddy Simulation（LES）, the effects of inlet turbulence intensities on the combustion efficiency was concentrated in this paper. With analyzing and comparing the results of the velocity fields, temperature fields, concentration fields and vorticity fields, the results show that with the increasing of inlet turbulence intensities of premixed fuel, the reaction is more strenuous, and the combustion efficiency would be improved, the length of flame would be cut down, at the same time the region of CO generating is narrowed and the quantities is reduced significantly. The results of this paper would provide some reference frame to improve the combustion efficiency in gas turbine and to reduce the pollutant emission.