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Simultaneous Laser Measurements of Local Values of Turbulence and Burning Velocity of Flames Propagating in Fuel-air Mixtures in Closed Combustion Chambers.

同时激光测量封闭燃烧室中燃料空气混合物中火焰传播的湍流和燃烧速度的局部值。

基本信息

批准号：
03452132
负责人：
HAMAMOTO Yoshisuke
金额：
$ 0.7万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

The research for clarifying the interaction between turbulence of fuel-air mixture and burning velocity is one of the most important subjects for the study on premixed combustion, and many research papers have been published. In the previous experimental research works, however, the relation between the local values of turbulence and the average values of burning velocity in total flames have been discussed. For the profound understanding of turbulent premixed combustion, it is necessary to measure simultaneously the local values of the burning velocity and the turbulence. The purpose of this study is the development of such a measurement method.In this study, nonintrusive methods for determining the local values of burning velocity of flames, turbulence characteristics and temperatures of unburned mixture in closed combustion chambers, were developed. The velocity of unburned mixture ahead of a flame front was measured with a laser Doppler velocimeter, and the flame propagation speed was simultaneously determined by measuring the time of flame travel over a fixed distance. The flame front was detected by the refraction of a laser beam due to the rapid change in the refractive index at the flame front. The burning velocity can be determined as the difference between the flame propagation speed and the unburned mixture velocity. The velocity data of unburned mixture were separated to the mean velocity and the turbulence intensity by using digital filter method. Further, the temperature change in unburned mixture with the compression due to combustion was measured by a laser interferometry. The experiments were carried out under several kinds of conditions of the turbulence characteristics and the equivalence ratio of propane-air homogeneous mixture in closed combustion chambers.

阐明燃油-空气混合物湍流与燃烧速度之间相互作用的研究是预混燃烧研究中最重要的课题之一，已经发表了许多研究论文。然而，在之前的实验研究工作中，已经讨论了湍流局部值与全火焰燃烧速度平均值之间的关系。为了深刻理解湍流预混燃烧，有必要同时测量燃烧速度和湍流的局部值。本研究的目的是开发这样一种测量方法。在本研究中，开发了用于确定封闭燃烧室中火焰燃烧速度、湍流特性和未燃烧混合物温度的局部值的非侵入式方法。使用激光多普勒测速仪测量火焰前锋前方未燃烧混合物的速度，并通过测量火焰在固定距离上传播的时间来同时确定火焰传播速度。由于火焰前锋处折射率的快速变化，通过激光束的折射来检测火焰前锋。燃烧速度可以确定为火焰传播速度与未燃烧混合物速度之间的差。利用数字滤波方法将未燃烧混合物的速度数据分离为平均速度和湍流强度。此外，通过激光干涉法测量未燃烧混合物中由于燃烧而压缩的温度变化。在密闭燃烧室中丙烷-空气均质混合气的湍流特性和当量比的几种条件下进行了实验。