Fundamental Study on The Mechanism of Turbulent Combusiton and Its Model

当我们考虑到世界范围内的能源问题和理想情况的持续性时，有必要建立科学的程序来促进能源的有效利用和减少污染物的排放。湍流燃烧机理的阐明和燃烧的控制是实现这一目标的关键。本研究的主要目的之一是获得与火焰结构有关的知识，这些火焰结构随反应和湍流强度的各个步骤的组合而变化，并了解燃烧反应和湍流之间的相互作用。另一个目的是提出一个燃烧模型的基础上的实验，可以应用于控制燃烧。结果表明：（1）湍流火焰的火焰结构随混合物当量比的减小而由收缩层流火焰结构转变为分布反应区火焰结构。通过缩短混合特征时间尺度和增加化学特征时间尺度模拟的低Damklane数火焰显示出相似的火焰结构。2）所提出的燃烧模型的基本特征是化学和混合控制的反应速率随局部Damklane数的变化而变化。该模型能成功地预测典型湍流火焰中光滑的时均温度分布，且该分布依赖于局部达姆克茨数的分布。由于湍流模型的精度与当地的Damk数密切相关，因此湍流长度尺度也与当地的Damk数密切相关，因此对湍流模型的讨论值得进一步研究。

When we think of the world wide energy issue and the persistence of desirable circumstances, it is necessary to establish the scientific procedure to promate both the effective utilization of energy and the reduction of pollutant emissions. The elucidation of turbulent combustion mechanism and the control of combustion are essential for the purpose. One of the main objects of the present study is to obtain knowledge related to flame structures varying with the combination of various steps of reaction and turbulence intensity and to understand the interaction between combustion reaction and turbulence. Another object is to propose a combustion model based on the experiments which can be applied for the control of combustion. The following conclusions are obtained.1) Flame structure of a turbulent flame changes from the structure of a srinkled laminar flame into that of a distributed reaction zone when the wquivalence ratioof the mixture is decreased in spite of a weak turbulence. Low Damkoler number flames fealized by shortened mixing characteristic time scale and by increased chemical characteristic time scale showed similar flame structure.2) The fundamental feature of the propased combustion model consists of chemistry- and mixing-controlled reaction rates which vary with the local Damkoler number. The smooth time-averaged temperature profile in a typical turbulent flame can be successfully predicted by the present nodel which is dependent on the distribution of local Damkoler numbers. Since the accuracy of the model is intimately related with the local Damkoler number, hence the turbulence length scale, discussion of turbulence model inflames beeds a future study.