Relationship between the Fine Flame Structure and the Local Flame Quenching Mechanism in the High Intensity Turbulent Propagating Flame

湍流既能提高预混气的燃烧速度，又能熄灭火焰。湍流对内燃机湍流燃烧过程的影响取决于湍流混合与化学反应的复杂相互作用。因此，为了弄清火焰局部熄灭与火焰精细结构的关系，有必要研究湍流混合和化学反应对它们的影响。本研究从实验和理论两个方面进行了研究，实验中采用纹影照相和激光片层层析成像技术观察火焰的精细结构，并采用被动式静电探针探测火焰区的火焰。通过实验研究，得到了火焰面曲率及其随独立控制燃烧的变化规律，火焰区内的小火焰数从1到6，随燃烧室温度比的增加而增加。 关于我们 层流燃烧速度与燃烧强度的关系。火焰的纹影照片表明了该区域中火焰的岛状特征，并得到被动静电探针方法揭示的多火焰事实的支持，但可能由于断层图像的对比度不足，尚未通过激光片层成像观察到。对几种层流燃烧速度较低的混合物，实验确定了火焰熄灭的条件，在理论研究中，建立了描述从层流到湍流的预混燃烧的模型，并提供了火焰结构和湍流燃烧速度的参数。为了阐明火焰结构与湍流燃烧速度之间的关系，本文指出了目前用于描述火焰结构相直径的三个坐标系（Re-Da，η_K/η_0-u '/S_<L0>，L/η_0-u'/S_<L0>）之间的相互关系，并将模型预测的燃烧速度和火焰结构参数以图表的形式表示出来。少

Turbulence can increase the burning velocity of premixed mixture, it can extinguish the flame, either. The effects of turbulence on the turbulent combustion process in internal combustion engines depend on the complicated interaction of the turbulent mixing with the chemical reaction therein. Therefore, to clarify the relation of the local flame quenching with the fine flame structure, it is necessary to investigate how they are affected by the turbulent mixing and chemical reaction. This has been done experimentally and theoretically in this study.In the experimental study, the schlieren photography and laser-sheet tomography were used to visualize the fine structure of the flame, and passive electrostatic probes to detect the flamelets from the flame zone. By the experimental work, the curvature of the flamelets and its variation with independently controlled combustion was visualized and the flamelet number in the flame zone measured from 1 to 6, increasing with the ratio of the tur … More bulence intensity to the laminar burning velocity. The islandlike feature of the flamelets in the zone was suggested by schlieren photographs of the flame and supported by the multi-flamelet fact revealed by the passive electrostatric probe method, but has not yet observed by the laser-sheet tomography probably owing to the deficient contrast of the tomograms. The conditions for flame quenching have also been determined experimentally for several mixtures with relatively low laminar burning velocities.In the theoretical study, such a model has been developed which describes the premixed combustion from laminar to turbulent flames, and provides parameters for the flame structure as well as the turbulent burning velocity. In order to clarify the relationship between the flame structure and turbulent burning velocity, three coordinate systems (Re-Da, eta_K/eta_0-u'/S_<L0>, L/eta_0-u'/S_<L0>) SO far used for the flame structure phase-dia, , rams individually, were shown to be related to one another and used to present the model-predicted burning velocities and flame structure parameters in the form of diagrams. Less