湍流预混燃烧逆梯度输运分布的数值研究

Numerical Study on Distribution of Counter Gradient Transport in Turbulent Premixed Combustion

关键词:  湍流预混燃烧  逆梯度输运  湍流火焰封闭模型  准一维计算

Key words:  Turbulent premixed combustion  Counter gradient transport  Turbulent Flame Closure model  Quasi-one-dimensional calculation

摘要:

为了研究湍流预混火焰中逆梯度输运现象的发展、空间分布规律和相关流场控制因素，基于湍流火焰封闭模型(Turbulent Flame Closure,TFC)机理进行准一维分析，得出了当地标量通量的逆梯度输运分量随预混燃烧反应进度变量的关系。通过Moreau燃烧室模型的数值模拟,验证了准一维分析结果的适用性。在此基础上，通过多工况计算，对比研究了密度比对流场逆梯度输运分布的影响。结果表明：预混燃烧流场中标量通量的逆梯度输运现象总发生在火焰中更靠近未燃混合物一侧；增大密度比, 流场逆梯度输运特性增强且其区域向反应物侧靠拢。

Abstract:

In order to study the development pattern, spatial distribution and controllable factors of counter gradient transport phenomenon in turbulent premixed flame, a theoretical deduction based on the TFC model via quasi-one dimensional analysis is conducted，where the relationship between local counter gradient transport component of scalar flux and progress variable is obtained. The applicability of the theory is verified by numerical simulation of the Moreau combustion chamber. On this basis, the multi-case calculation is operated to discuss the effects of density ratio on the distribution of counter gradient transport. The results show that the counter gradient transport of scalar flux in the premixed combustion flow field always occurs in the area close to the unburned mixture. Increasing the density ratio, the counter gradient transport property will be enhanced while its region getting closer to the reactant.