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Turbulence effects during evaporation of drops in clusters

Bellan, J. and Harstad, K. (1988) Turbulence effects during evaporation of drops in clusters. International Journal of Heat and Mass Transfer, 31 (8). pp. 1655-1668. ISSN 0017-9310. http://resolver.caltech.edu/CaltechAUTHORS:20171025-105336722

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Abstract

A model of droplet evaporation in clusters and the exchange processes between the cluster and the gas phase surrounding it are presented. This model is developed for use as a subscale model in calculations of spray evaporation and combustion and thus described only global features of cluster behavior. The gas pressure in the cluster remains constant during evaporation and as a result the volume of the cluster and the drop number density inside the cluster vary. Two turbulence models are considered. The first one describes cluster evaporation in surroundings initially devoid of turbulence and turbulence is allowed to build up with time. The second model describes cluster evaporation in surroundings where turbulence is present initially. The results obtained with these models show that turbulence enhances evaporation and is a controlling factor in the evaporation of very dense clusters; examples are shown where with the first turbulence model saturation was obtained before complete evaporation whereas the opposite was obtained with the second turbulence model. As the initial air/fuel mass ratio increases, both turbulence history and the initial relative velocity between drops and gases can control evaporation. It is shown that the evaporation time decreases with an initial increase in turbulence levels or relative velocity. When the initial air/fuel mass ratio increases further and the initial drop number density falls within the dilute regime, neither of the above parameters can control evaporation. Moreover, the evaporation time decreases with the decreasing size of the cluster for dense clusters of drops, whereas for dilute clusters of drops the size is not a controlling factor. The practical implications of these results are discussed.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/0017-9310(88)90278-5DOIArticle
http://www.sciencedirect.com/science/article/pii/0017931088902785?via%3DihubPublisherArticle
Additional Information:© 1988 Elsevier Ltd. Received 9 June 1987, Accepted 22 January 1988.
Record Number:CaltechAUTHORS:20171025-105336722
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20171025-105336722
Official Citation:J. Bellan, K. Harstad, Turbulence effects during evaporation of drops in clusters, In International Journal of Heat and Mass Transfer, Volume 31, Issue 8, 1988, Pages 1655-1668, ISSN 0017-9310, https://doi.org/10.1016/0017-9310(88)90278-5. (http://www.sciencedirect.com/science/article/pii/0017931088902785)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:82657
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Oct 2017 18:43
Last Modified:25 Oct 2017 18:43

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