著者

倉林 俊雄 柄沢 隆夫 小林 孝徳

出版者

一般社団法人 日本エネルギー学会

雑誌

燃料協会誌 (ISSN:03693775)

巻号頁・発行日

vol.57, no.11, pp.904-911, 1978-11-20 (Released:2010-06-28)

参考文献数

1

被引用文献数

1

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The immersion liquid sampling method is widely used to determine spray droplet sizes for its simple principle and easy sampling technique, but the method has some problems unsettled which we should be cautious of when we adopt it. The coalescence of droplets in the immersion liquid is one of them and is liable to cause an unexpected increase of measured diameter.By considering a simplified model for sampling of droplets, theoretical formulas for possibility of the coalescence and for increase rate of mean diameter due to the coalescence have been derived. The calculated values were compared with measured ones under various spraying and sampling conditions. While quantitative agreement between them was not acheaved, it was confirmed the calculated values agree quite well with measured ones qualitatively and the formulas are applicable to analyse the effects of various factors on the coalescence and on the increase of mean diameter.The following items have been revealed by this theory and the related experiments.1. The increasing number of droplet, the higher viscosity of immersion liquid, the larger nozzle hole and the smaller droplet diameter have tendency to increase the mean diameter due to the droplet coalescence.2. It should be avoided to bring the sampling position too close to the noz-zle.3. Discharge velocity of the jet does not affect on the droplet coalescence and on the increase of mean diameter remarkably.

著者

志賀 聖一 江原 秀治 柄沢 隆夫 倉林 俊雄

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.51, no.471, pp.3823-3827, 1985-11-25

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In previous paper, it was suggested the effect of exhaust gas recirculation (EGR) on the diesel knock is relevant to the reaction rate of spontaneous ignition which occurs at the initial stage of diesel combustion. In a present study, this suggestion is verified by measuring the ignition lag and separating it into physical and chemical lags by applying the statistical technique presented by S. Kumagai. Under the operating condition used in this study, the physical lag is rather longer than the chemical lag and hardly changes with an increase in EGR ratio. On the other hand, the chemical lag is considerably affected by EGR. Though the dependent behaviour of the chemical lag on EGR is not simple, it is clearly shown that the tendency of chemical lag versus EGR ratio is quite the reverse of that of the diesel knock intensity. This means that the diesel knock intensity with EGR is dominated by the reaction rate of spontaneous ignition.