Turbulent flames are intrinsically curved. In the presence of preferential diffusion, curvature effects either enhance or suppress molecular diffusion, depending on the diffusivity of the species and the direction of the flame curvature. When a tabulated chemistry type of modeling is employed, curvature-preferential diffusion interactions have to be taken into consideration in the construction of manifolds. In this study, we employ multistage stage flamelet generated manifolds (MuSt-FGM) method to model autoigniting non-premixed turbulent flames with preferential diffusion effects included. The conditions for the modeled flame are in MILD combustion regime. To model the above-mentioned curvature-preferential diffusion interactions, a new mixture fraction which has a non-unity Lewis number is defined and used as a new control variable in the manifold generation. 1D curved flames are simulated to create the necessary flamelets. The resulting MuSt-FGM tables are used in the simulation of 1D laminar flames, and then also applied to turbulent flames using 2D direct numerical simulations (DNS). It was observed that when the curvature effects are included in the manifold, the MuSt-FGM results agree well with the detailed chemistry results; whereas the results become unsatisfactory when the curvature effects are ignored.

湍急的火焰本质上是弯曲的。在存在优先扩散的情况下，取决于物质的扩散率和火焰曲率的方向，曲率效应会增强或抑制分子扩散。当使用列表化学类型的建模时，在歧管的构造中必须考虑曲率-优先扩散相互作用。在这项研究中，我们采用多级小火焰产生歧管（MuSt-FGM）方法来模拟自动点火的非预混湍流火焰，并包括优先扩散效应。建模火焰的条件为轻度燃烧。为了模拟上述曲率-优先扩散相互作用，定义了具有非统一路易斯数的新混合分数，并将其用作歧管生成中的新控制变量。模拟一维弯曲火焰以创建必要的小火焰。生成的MuSt-FGM表用于一维层流火焰的模拟，然后还使用二维直接数值模拟（DNS）应用于湍流火焰。观察到，当歧管中包含曲率效应时，MuSt-FGM结果与详细的化学结果非常吻合；当忽略曲率效应时，结果将不令人满意。观察到，当歧管中包含曲率效应时，MuSt-FGM结果与详细的化学结果非常吻合；当忽略曲率效应时，结果将不令人满意。观察到，当歧管中包含曲率效应时，MuSt-FGM结果与详细的化学结果非常吻合；当忽略曲率效应时，结果将不令人满意。