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Mixing and combustion with low heat release in a turbulent shear layer

Mungal, M. G. and Dimotakis, P. E. (1984) Mixing and combustion with low heat release in a turbulent shear layer. Journal of Fluid Mechanics, 148 . pp. 349-382. ISSN 0022-1120. http://resolver.caltech.edu/CaltechAUTHORS:20120709-071921964

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Abstract

Turbulent mixing and combustion are investigated in a gaseous shear layer formed between two streams: one containing a low concentration of hydrogen in nitrogen and the other containing a low concentration of fluorine in nitrogen. The resulting temperature field is measured simultaneously at eight points across the width of the layer using fast-response cold-wire thermometry. The results show the presence of large, hot structures separated by tongues of cool fluid that enter the layer from either side. The usual bell-shaped mean-temperature profiles therefore result from a duty cycle whereby a fixed probe sees alternating hot and cool fluid, which results in the local mean. The adiabatic flame temperature is not achieved in the mean, at any location across the layer. For fixed velocities, it is found that, in general, two different mean-temperature profiles result from a given pair of reactant compositions if the sides of the layer on which they are carried are exchanged (‘flipped’). This finding is a direct consequence of the asymmetric entrainment of fluid into the layer. Results are compared with the predictions of Konrad and discussed in the context of the Broadwell–Breidenthal model. By comparison with the liquid result of Breidenthal, the amount of product formed in the layer at high Reynolds number is found to be dependent upon the Schmidt number. Results for a helium–nitrogen layer are discussed briefly.


Item Type:Article
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http://dx.doi.org/10.1017/S002211208400238X DOIUNSPECIFIED
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=377592&fulltextType=RA&fileId=S002211208400238XPublisherUNSPECIFIED
Additional Information:© 1984 Cambridge University Press. Published Online April 20 2006. Received September 19 1983. Revised June 4 1984. We would like to acknowledge the significant contributions of B. J. Cantwell and G. L. Brown during the earlier phases of this work, the assistance of J. C. Hermanson and C. E. Frieler in the research reported here, as well as the expert help of Mr Earl Dahl throughout. The many enlightening discussions, critical comments, enthusiastic support and good humour of J. E. Broadwell were especially valuable, and are most appreciated. This work was sponsored by the Air Force Office of Scientific Research contracts F44620-76-C-0046 and F49620-79-C-0159.
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Funding AgencyGrant Number
Air Force Office of Scientific Research (AFORS) F44620-76-C-0046
Air Force Office of Scientific Research (AFOSR)F49620-79-C-0159
Record Number:CaltechAUTHORS:20120709-071921964
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20120709-071921964
Official Citation: M. G. Mungal and P. E. Dimotakis (1984). Mixing and combustion with low heat release in a turbulent shear layer. Journal of Fluid Mechanics, 148 , pp 349-382 doi:10.1017/S002211208400238X
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32291
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:09 Jul 2012 14:54
Last Modified:21 Oct 2014 15:36

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