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Visualization of Mechanical Processes: An International Online Journal


ISSN Online: 2152-209X

Visualization of Mechanical Processes: An International Online Journal

DOI: 10.1615/VisMechProc.2013003813

VERIFICATION OF CH* EMISSION IMAGING TECHNIQUE AS A MEASURE OF A FLAME'S OVERALL HEAT RELEASE RATE ON A NON-SOOTING METHANE DIFFUSION MICROFLAME

Taro Hirasawa
Department of Mechanical Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, 487-8501, Japan
Kunihiro Gotanda
Department of Mechanical Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, 487-8501, Japan
Yuichi Kamata
Kamata Science Works, 402-12 Akechi-cho, Kasugai, 487-0303, Japan
Yuji Nakamura
Division of Mechanical and Space Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo 060-8628, Japan

ABSTRACT

The methodology to obtain combustion characteristics, such as overall heat release rate and heat loss rate based on the received power of CH* emission, is investigated in the present study. First, the relation between the power of CH* emission received on a CCD and the total power of CH* emission from flames, i.e., radiant power from a flame in the CH* emission band, has been examined theoretically and experimentally. The optically thin flame assumption needs to hold in order to obtain the normalized total power of emission, from the normalized received power of emission based on line-of-sight imaging. The optically thin flame assumption on the CH* and H2O emission band has been experimentally verified by taking CH* and H2O emission images from different observation angles. This assumption is shown to hold under non-sooting microflames. Therefore the received power of emission from the flame, obtained by integrating the intensity on the CH* emission image, is shown to be directly proportional to the total power of CH* emission. It is experimentally demonstrated that the relative variation of the flame's overall heat release rate can be estimated by the CH* emission imaging technique based on measurement of the received power of CH* emission under the condition of constant heat loss rate or known heat loss rate. This is useful to estimate the performance of burners, especially microburners or microcombustors.