多维火焰面求解燃烧场中的多机制火焰结构

Multi-dimensional Flamelet Generated Manifolds for Combustion Simulation with Multi-Regime Flame Structure

关键词:  多维层流火焰面模型  Strang分裂算法  交互迭代修正  层流抬举火焰

Key words:  Multi-dimensional flamelet generated manifolds  Strang splitting algorithm  Interactive correction  Laminar lifted flame

摘要:

火焰面模型已被广泛应用于层流和湍流火焰的模拟中，然而对包含多种火焰机制的复杂燃烧场，针对单一火焰机制的一维层流火焰面模型不能准确地还原其内部的火焰结构特征。为了解决以上问题，基于由Nguyen等提出的多维火焰面生成流形方法(MFM)，发展了一种新的交互迭代式Z-C多维火焰面模型。通过层流抬举火焰的模拟，以直接求解详细化学反应的DNS解为参照解，以确定新模型的模化精度，并与一维预混火焰面生成流形方法(premixed FGM)进行了对比。通过对不同模型解的分析可以得出，相比于只能捕捉一种火焰特征的一维火焰面模型，多维火焰面模型可以同时捕捉多机制火焰结构中的扩散和预混特征。使用新的多维火焰面模型求解可以在计算量减小一个数量级的前提下，得到接近DNS参照解的模型精度。

Abstract:

Flamelet models have been applied to both laminar and turbulent flame simulations. As for complex combustion systems with multi-regimes，single-dimensional flamelet models based on single flame regime solving cannot reproduce local flame structure accurately. To overcome such deficiencies，a new interactive Z-C multi-dimensional flamelet modeling approach has been developed，which is based on the concept of multi-dimensional flamelet generated manifolds (MFM) proposed by Nguyen et al. Numerical simulation of a laminar lifted flame has been carried out to verify modeling accuracy for this new approach，with DNS solutions obtained using detailed chemistry scheme as references，and has been compared with single-dimensional premixed flamelet generated manifolds approach(premixed FGM). Analyses of different modeling solutions indicate that multi-dimensional flamelet model can capture both non-premixed and premixed characteristic of the multi-regime flame structure，comparing to single-dimensional flamelet models which can capture only one flame regime. Application of this new multi-dimensional flamelet model can lead to modeling accuracy close to DNS reference solutions，with computation efforts reduced by an order of magnitude.