著者

牧野 敦

出版者

一般社団法人 日本燃焼学会

雑誌

日本燃焼学会誌 (ISSN:13471864)

巻号頁・発行日

vol.55, no.172, pp.94-109, 2013 (Released:2018-01-26)

参考文献数

38

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Particle combustion of solid carbon in the quiescent atmosphere has been overviewed by use of accomplishment in the aerothermochemical analyses, in which not only the surface C-O2 and C-CO2 reactions but also the gas-phase CO-O2 reaction is taken into account. By virtue of the generalized species-enthalpy coupling functions, close coupling of those reactions has been elucidated. It has been identified that the combustion response in the three limiting situations, such as the Frozen, the Flame-detached and the Flame-attached modes, can be described analytically, by using the generalized coupling functions. Explicit combustion-rate expressions by use of the transfer number in terms of the natural logarithmic term, just like that for droplet combustion, have further been obtained for the combustion response in the limiting situations. In addition, by examining establishment of CO-flame over the carbon particle, it has been confirmed that the combustion rate can fairly be represented by the expression in the Frozen mode when the particle diameter is 100 μm or less. Since this expression is explicit and has fair accuracy, various contributions are anticipated not only qualitatively but also quantitatively. Combustion response in the transient situation has further been examined, from which an existence of the critical size for the particle burn-out has even been derived. A fair degree of agreement in experimental comparisons indicates that the present formulation has captured the essential features of the particle burn-out.

著者

新冨 雅仁 牧野 敦 藤井 淳志 荒木 信幸

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:03875016)

巻号頁・発行日

vol.69, no.678, pp.476-481, 2003

被引用文献数

1

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An experimental study has been conducted in order to elucidate influences of additions of hydrogen and methane on the combustion synthesis of diamond films. Differences between the flat flame and the conical flame are first examined, and it is reconfirmed that the velocity gradient is one of the dominant parameters in the combustion synthesis of diamond films. Additions of hydrogen and/or methane are examined on the growth rates of diamond films, crystal sizes, and morphology. These results are also confirmed by conducting the similar experiments with a welding torch, instead of the flat flame burner. It is found that an addition of hydrogen reduces the growth rate and crystal size, while that of methane enhances those although homogeneity of the diamond films is reduced.

著者

新冨 雅仁 牧野 敦 藤井 淳志 荒木 信幸

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:03875016)

巻号頁・発行日

vol.68, no.675, pp.3136-3143, 2002

被引用文献数

1

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An experimental study to synthesize diamond films has been conducted under a well-defined flow field to make clear the mechanism of combustion synthesis of diamond films. Using a flat flame burner, the homogeneous diamond films are synthesized on substrates, above which flat, premixed acetylene/hydrogen/oxygen flames are established. The effect of equivalence ratio and velocity gradient is examined on the growth rates of diamond films, crystal sizes, and their morphology. It is found that not only the maximum growth rate but also the maximum crystal size can be obtained when the equivalence ratio is about 2.50, and that the growth rate, crystal size, and/or morphology are nearly the same when the velocity gradient is kept constant. These results are confirmed by a conical flame with a welding torch. In addition, the scratching treatment for the substrates by diamond powder is unnecessary, the maximum growth rate of diamond films can be obtained when the surface roughness is about 0.11 μm, and the nuclei of diamond appear in scratches on the substrates.