Acoustic Excitation of Organized Eddy Structure and Dual diffusion Flames Behind a Rear-Facing Simicircular Cylinder

后向圆柱体后面有组织的涡流结构和双扩散火焰的声激发

• 批准号: 06650243
• 负责人: OHIWA Norio
• 金额: $ 1.28万
• 依托单位: Nagoya Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650243/
• 关键词: Turbulent diffusion flame; Active combustion control; Coherent structure; Phase-locked averaging; Sound-flame interaction; Flame-flow interaction; Wake flame; K-H instability; 非対称渦構造; 組織的構造; 位相平均化; 音と流れの相互作用; 火炎と流れの相互作用; 乱流燃焼; 拡散火炎; 物体後流

Two types of dual diffusion flames established behind a rear-facing semicircular fuel nozzle were experimentally investigated ; one is the plane diffusion flame consisiting of an ordinary laminar diffusion flame on the lower-velocity side of the fuel nozzle and a lifted flame on the higher-velocity side, the other the bluffbody stabilized wake flame composed of two lifted flames on both sides of the fuel nozzle. The computer-aided phase-locked averaging method (the CAPLA method for short) was combined with the acoustic excitation to examine not only effects of the acoustic excitation on the flam estructure, but also phase characteristics of the formation processes of organized eddies and eddy-flames. The acoustic excitation was apploed by a flat loud-speaker flush-mounted on the higher-velocity side wall of the combustion tunnel at a constant frequency of 300Hz.According to flash shadowgraphs of flames the acoustic excitation was found to make the outline of eddy-flames clear with incr … More easing the excitation intensity due to rapid and clear formation of organized eddies, leaving general features of flames almost unvaried. Frequency spectra of fluctuating temperature and ion current intensity for two kinds of flames showed that, at the maximum excitation intensity applied, only the fundamental peak at 300Hz and some of its harmonics were observed without exhibiting any white noise character. Therefore, it was proved that the acoustic excitation is very usefulin the phase-locked-averaging measurements of turbulent flames.Two dimensional phase-averaged temperature and ion current intensity profiles at eight consecutive phases obtained for two kinds of dual flames demonstrated clearly the entire process from the formation of an organized eddy to the establishment of an eddy-flame. As a result, an organized eddy-flame in the plane diffusion flame was found to have an mean lifetime of about three times the period of organized eddy formation of 1/300 sec, while the lifetime of an organized eddy-flame in the wake flame was about twice the period of the organized eddy formation. Less

实验研究了后向半圆形燃料喷嘴后形成的两种双扩散火焰：一种是由燃料喷嘴低速侧的普通层流扩散火焰和高速侧的升力火焰组成的平面扩散火焰，另一种是由燃料喷嘴两侧的两个升力火焰组成的钝体稳定尾流火焰。将计算机辅助锁相平均法（简称CAPLA法）与声激励相结合，不仅研究了声激励对火焰结构的影响，而且研究了有序涡和涡流火焰形成过程的相位特性。声激励是通过安装在燃烧室高速侧壁上的平板扬声器在300 Hz的恒定频率下施加的。根据火焰的闪光阴影图，发现声激励使涡流火焰的轮廓清晰，并随着火焰强度的增加而增加。 ...更多信息 由于快速而清晰地形成有组织的涡流，从而缓和了激发强度，使火焰的一般特征几乎不变。两种火焰的温度和离子流强度脉动频谱表明，在最大激发强度下，只观察到300 Hz的基波峰及其部分谐波，没有表现出任何白色噪声特征。本文给出了两种双火焰在八个连续相位上的二维相平均温度和离子流强度分布，清晰地显示了从有组织涡的形成到涡火焰建立的全过程。结果发现，平面扩散火焰中有组织的涡流火焰的平均寿命约为有组织的涡流形成周期1/300秒的三倍，而尾流火焰中有组织的涡流火焰的寿命约为有组织的涡流形成周期的两倍。少

项目成果

ISHINO Y.,ABE T.,OHIWA N.,YAMAGUCHI S.: "Acoustic Excitation of Dual Diffusion Flames with Coherent Structure Behind a Rear…facing Semicircular Cyilnder" Proceedings of 26th International Symposium on Combustion(1996-8). (投稿中).

ISHINO Y.、ABE T.、OHIWA N.、YAMAGUCHI S.：“后部…面向半圆形圆柱体后面具有相干结构的双扩散火焰的声学激发”第 26 届国际燃烧研讨会论文集（1996-8）。已提交））。

ISHINO Y., ABE T., OHIWA N., YAMAGUCHI S.: "Acoustic Excitation of Turbulent Diffusion Flames with Coherent Structure Behind a Rear-facing Semicircular Cyilnder" Proceedings of 33rd National Symposium on Combustion. 496-498 (1995)

ISHINO Y.、ABE T.、OHIWA N.、YAMAGUCHI S.：“后向半圆形圆柱体后面具有相干结构的湍流扩散火焰的声学激发”第 33 届全国燃烧研讨会论文集。

ISHINO Y., ABE T., OHIWA N., YAMAGUCHI S.: "Acoustic Excitation of Dual Diffusion Flames with Coherent Structure Behind a Rear-facing Semicircular Cyilnder" To be appeared in The Proceedings of 26th International Symposium on Combustion. (1996)

ISHINO Y.、ABE T.、OHIWA N.、YAMAGUCHI S.：“后向半圆形圆柱体后面具有相干结构的双扩散火焰的声学激发”将发表在第 26 届国际燃烧研讨会论文集上。

石野,阿部,大岩,山口: "半円柱後流に形成された非対称渦構造をもつ拡散火炎の音響励起" 第33回燃焼シンポジウム講演論文集. 496-498 (1995)

Ishino、Abe、Oiwa、Yamaguchi：“半圆柱体尾流中形成的具有不对称涡流结构的扩散火焰的声学激发”第 33 届燃烧研讨会论文集 496-498 (1995)。

ABE T., ISHINO Y., OHIWA N., YAMAGUCHI S.: "Acoustic Excitation of Organized Eddy Structure and Diffusion Flames Behind a Rear-Facing Semicircular Cylinder" Proceedings of 32nd National Symposium on Combustion. 474-476 (1994)

ABE T.、ISHINO Y.、OHIWA N.、YAMAGUCHI S.：“后向半圆柱体后面有组织涡流结构和扩散火焰的声学激发”第 32 届全国燃烧研讨会论文集。