耦合天然气详细反应机理的三维湍流预混火焰结构数值预测

Three-Dimensional Numerical Prediction of the Structure of Turbulent Premixed Flame for Natural Gas Using Linked CFD and Detailed Chemical Kinetics

以具有279机理的天然气燃烧为例,分别采用涡耗散概念EDC湍流燃烧模型、修正的涡旋破碎EBU湍流燃烧模型以及基于时均值的Arrhenius关系,对燃烧室内复杂的湍流反应流进行了三维数值模拟,并对预测结果进行了分析.结果表明,EDC模型可以较好地反映湍流化学作用,并且能够较好地描述各基元反应,从而为工程实际复杂燃烧情况下其有害排放、中间物质、自由基和痕迹物质生成机理的研究提供基础.

This paper presents the results of a detailed study of the eddy dissipation concept (EDC) and modified eddy break-up (EBU) model as well as Arrhenius relations (with turbulent effects ignored) respectively applied to a 3-D premixed flame in a chamber. The objectives are to find out how EDC turbulent combustion model can represent the complex chemistry and the turbulence-chemistry interactions can be described by this modeling method. A 279-step chemical mechanism is used to predict rates of reaction in natural gas and air mixtures. It is shown that the temperature and concentration values of the major species predicted by EDC and EBU are consistent and the computational results by simple Arrhenius relations are clear deviations. It indicates the importance of turbulent mixing in turbulent flames.