旋流燃烧器复合小火焰模型的大涡模拟

Large Eddy Simulation of a Swirl Combustor With a Combined Flamelet Model

对低旋燃烧器内的流动和燃烧进行了大涡模拟,其中化学反应分别采用传统的扩散小火焰模型和所提出的复合小火焰模型描述。复合小火焰模型借助于燃烧区索引的概念区分当地的燃烧模式,若当地的燃烧为扩散燃烧,则调用扩散小火焰库,否则调用预混小火焰库。数值结果与实验数据的对比表明,采用大涡模拟方法结合小火焰模型能够很好地模拟实验室尺度的低旋燃烧器,且采用复合小火焰模型能够得到更加符合实际的结果。

Large-eddy simulation was employed to study the turbulent flow and combustion in a low swirl combustor. The chemical reaction was described using the traditional diffusion flamelet model and the combined fiamelet model. The combined flamelet model distinguishes the local combustion mode using the combustion regime index concept. If the local combustion regime was diffusion combustion, then the diffusion flamelet library would be utilized, otherwise the premixed flamelet library would be called. The comparison between numerical results and experimental data indicates that large-eddy simulations with flamelet models are able to predict the laboratory-scale low swirl combustor very well, and the combined flamelet model has better predictive ability.