Structure and Dynamic Behavior of Flamelet with Strain as Turbulent Combustion Elementary Process

湍流火焰是由承受应变的小火焰组成的，弄清小火焰的结构和动力学行为，对于理解湍流火焰的结构和特性，建立合理的分析方法是非常有用的。因此，本研究旨在通过实验和直接数值分析的方法，阐明火焰结构、火焰应变控制下的熄火特性、局部熄火引起的边缘火焰结构和动力学行为，这与火焰应变率的正负、曲率效应、优先扩散、应变率的非定常性和局部性有关。(1)By对以氢气和甲烷为燃料的对流层流扩散火焰进行了考虑基元化学反应和多组分扩散的数值分析，通过改变对流速度和局部喷入射流来控制应变速率和流量， 关于我们 分析了消光、应变速率和流场之间的关系。（2）对中心射流的正扩散火焰和反扩散火焰，通过声激励使火焰中的燃料或空气产生流速脉动，形成大尺度旋涡火焰，并利用瑞利散射和激光诱导荧光测量火焰中的温度和OH浓度分布，分析了旋涡与火焰的相互作用行为。（3）计算分析了火焰与旋涡相互作用对火焰结构和火焰熄灭的影响。当燃料速度波动相对较弱，火焰未熄灭时，组分间的优先扩散和Lewis数效应对火焰的温度特性有较大影响。当速度脉动较大时，放热率随化学非平衡过程而减小，最终导致熄火。少

The turbulent flame consists of the flamelet that receive the strain, and it is useful to clarify the structure and the dynamic behavior of the flamelet for understanding the structure and characteristics of turbulent flame, and establishing a reasonable analytical technique. Therefore, this research aims by an experiment and a direct numerical analysis to clarify flame structure, the extinction characteristics under the control of the flame strain, the structure and dynamic behavior of the edge flame caused by local extinction, which is related to the positive and negative flame strain rate, curvature effect, preferential diffusion, unsteadiness and locality of strain rate.(1)By the numerical analysis that considers elementary chemical reaction and multi-component diffusion of the opposing-flow laminar diffusion flame that uses hydrogen and the methane as a fuel, the strain rate and the flow are controlled by changing the opposing flow velocity and by injecting a jet locally, the rela … More tion among extinction, the strain rate, and the flow fields was analyzed.(2)The flow velocity fluctuation by the sound excitation was given to the fuel or air for the normal diffusion flame and the inverse-diffusion flame of a central jet flow, the flame with a large-scale vortex was formed, and the interacting behavior of the vortex and the flame was analyzed by two dimensional measurement of the temperature and the OH concentration profiles by the Rayleigh scattering and the laser-induced fluorescence.(3)The influence was computationally analyzed, which the interaction between a flame and a vortex gives on flame structure and extinction. When the fluctuation of fuel velocity relatively is weak and the flame does not result in extinction, the preferential diffusion between species and the Lewis-number effect give a large influence on the temperature characteristic of the flame. When the velocity fluctuation is large, the heat release rate decreases with the process of the chemical non-equilibrium, and it results in extinction. Less