Vaporization dynamics of functional droplets in a hot laminar air jet

Deepu, P and Basu, Saptarshi and Kumar, Ranganathan (2013) Vaporization dynamics of functional droplets in a hot laminar air jet. In: INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 56 (1-2). pp. 69-79.

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Abstract

The vaporization characteristics of pendant droplets of various chemical compositions (like conventional fuels, alternative fuels and nanosuspensions) subjected to convective heating in a laminar air jet have been analyzed. Different heating conditions were achieved by controlling the air temperature and velocity fields around the droplet. A hybrid timescale has been proposed which incorporates the effects of latent heat of vaporization, saturation vapor pressure and thermal diffusivity. This timescale in essence encapsulates the different parameters that influence the droplet vaporization rate. The analysis further permits the evaluation of the effect of various parameters such as surrounding temperature, Reynolds number, far-field vapor presence, impurity content and agglomeration dynamics (nanosuspensions) in the droplet. Flow visualization has been carried out to understand the role of internal recirculation on the vaporization rate. The visualization indicates the presence of a single vortex cell within the droplet on account of the rotation and oscillation of the droplet due to aerodynamic load. External heating induced agglomeration in nanofluids leads to morphological changes during the vaporization process. These morphological changes and alteration in vaporization behavior have been assessed using high speed imaging of the diameter regression and Scanning Electron Microscopy images of the resultant precipitate. (C) 2012 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	Copyright for this article belongs to PERGAMON-ELSEVIER SCIENCE LTD,ENGLAND
Keywords:	Droplet vaporization;Convective heating;Flow visualization;Nanosuspensions;Morphology
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	06 Feb 2013 12:18
Last Modified:	06 Feb 2013 12:18
URI:	http://eprints.iisc.ac.in/id/eprint/45718

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