预混湍流火焰面褶皱结构网络拓扑研究

湍流火焰结构是表征湍流与火焰相互作用的组分、速度、温度等标量场信息，理解湍流与火焰相互作用规律，验证和发展湍流燃烧模型的实验基础。针对传统曲率PDF分布反映湍流火焰面褶皱结构失准问题，利用网络拓扑结构方法可以标记系统关键节点和特征结构，构建湍流火焰面的拓扑结构。本文标记了湍流火焰面上的关键褶皱结构，分析了湍流与火焰的作用规律，结果表明:低湍流强度下，湍流火焰面的关键褶皱结构由火焰自身不稳定性引起；当湍流强度增大，湍流火焰面的关键褶皱结构由湍流尺度决定。在本生灯湍流火焰中，火焰自身不稳定性引起的火焰褶皱与火焰发展距离有关。在本生灯火焰底部，火焰自身不稳定性不引起火焰面褶皱，随着火焰向下游发展，其对火焰面影响逐渐增大，火焰褶皱程度增加。

Network topology analysis on wrinkled structure of turbulent premixed Bunsen flame

Turbulent flame structure represents the species, velocity and temperature field in the turbulent combustion, which reflects the interaction between the turbulence and the combustion. It is also important for combustion model validation. The conventional PDF of curvature method can not accurately reflect the folded regions in the turbulent flame, while the network topology analysis can demonstrate these regions as it can mark the key nodes or structure in a system. In this paper, the network structure of the turbulent premixed Bunsen flame is constructed to trace the folded regions in turbulent flames. Results show that the folded regions can be traced by network structure. These regions are mainly caused by DL instability in weak turbulence, while they are mainly affected by turbulence vortex wrinkling as turbulence intensity increases. The influence of DL instability on turbulent premixed Bunsen flames is constrained by flame development. At the bottom of Bunsen flame, the DL instability does not wrinkle the flame. As the flame propagates to the downstream, the flame becomes more wrinkled due to DL instability.