Decay of Turbulence near the Local Reaction Zone of A Turbulence Premixed Flame

湍流预混火焰局部反应区附近的湍流衰减

基本信息

批准号：
07650271
负责人：
FURUKAWA Junichi
金额：
$ 1.15万
依托单位：
Tokyo Metropolitan Technical College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650271/
关键词：
combustion premixed flame flame structure turbulence LDV electrostatic probe 予混合火災火災構造

项目摘要

An attempt has been made to measure the Kolmogorov scale of turbulence within the local reaction zone of a turbulent premixed flame established in a regime in which the Kolmogorov scale of turbulence in the non-reacting flow is smaller than the laminar premixed flame thickness. in order to measure the Kolmogorov scale of turbulence within the local reaction zone, the specially arranged diagnostics composed of the LDV system and the micro-electrostatic probe has been adopted. By using this technique, the velocity fluctuation within the local reaction zone can be successfully distinguished from that in unburned mixture or burned gas stream. Thus, the Kolmogorov scale of turbulence in the local reaction zone could be evaluated on the basis of the power spectrum density function derived from the velocity fluctuations.The powers spectrum density function, the turbulence intensity and the Kolmogorov scale of turbulence derived from velocity fluctuations in the approach flow are shown to be the same as those in the non-reacting flow. Also, the small scale eddies in the non-reacting flow, which are smaller than the laminar premixed flame thickness, are confirmed to exist in the approach flow.It is found that the approach flow turbulence increases in the local reaction zone because of the expansion of gases due to heat release. The Kolmogorov scale of turbulence derived from velocity fluctuations in the local reaction zone is shown to be much larger than the laminar premixed flame thickness. this result implies that the small scale eddies in the approach flow may not survive through the preheat zone.

已经尝试测量在湍流中建立的湍流预防火焰的湍流中的Kolmogorov量表，在该制度中，非反应流动中的Kolmogorov湍流比层小于层层次的预混合火焰厚度。为了测量局部反应区域内的湍流量表，采用了由LDV系统组成的特殊布置诊断和微静电探针。通过使用此技术，可以在未燃烧的混合物或燃烧的气流中成功区分局部反应区域内的速度波动。因此，可以根据速度波动得出的功率谱密度函数来评估局部反应区域中的湍流量表。强大频谱密度的功能，湍流强度，湍流和kolmogorov的湍流范围从速率波动中衍生而成，这些速度均与流量相同。同样，非反应流动中的小尺度涡流比层状预混合的火焰厚度小，已证实在接近流中存在。发现由于热量释放而导致的气体膨胀，因此局部反应区域的接近流动湍流增加。显示出源自局部反应区速度波动的湍流的Kolmogorov量表比层状预混合的火焰厚度大得多。该结果表明，进近流中的小规模涡流可能无法通过预热区域存活。