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The evaporation of the charged and uncharged water drops suspended in a wind tunnel

Bhalwankar, RV and Sathe, AB and Kamra, AK (2004) The evaporation of the charged and uncharged water drops suspended in a wind tunnel. Proceedings of the Indian Academy of Sciences, Earth and Planetary Sciences, 113 (2). pp. 129-138.

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Abstract

A laboratory experiment has been performed to study the effect of ventilation on the rate of evaporation of the millimeter sized charged and uncharged water drops suspended in a vertical wind tunnel. The linear relationship, f v = 0.907 + 0.282X, observed between the mean ventilation coefficient, f v, and a non-dimensional parameter X, (X = N Sc,v 1/3 N Re 1/2 where N Sc,v, is Schmidt number and N Re is Reynold's number) is in agreement with the results of earlier investigations for uncharged water drops. However, in case of charged drops carrying 10 -10C of charge, this relationship gets modified to f v = 0.4877 + 0.149X. Thus, the rate of evaporation of charged drops is slower than that of uncharged drops of the same size. Oscillations of the drop and the change in airflow around drops are suggested to contribute to lowering of the ventilation coefficients for charged drops. Applicability of the results to a small fraction of highly charged raindrops falling through the sub-cloud layer below thunderstorm is discussed. The relaxation time required for a ventilated drop to reach its equilibrium temperature increases with the drop size and is higher for the charged than for the uncharged drops. It is concluded that in a given distance, charged drops will evaporate less than that of uncharged drops.

Item Type: Article
Additional Information: Copyright of this article belongs to Indian Academy of Science
Uncontrolled Keywords: droplet; electric field; evaporation; mathematical analysis; raindrop; wind tunnel
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 18 Apr 2015 09:29
Last Modified: 18 Apr 2015 09:29
URI: http://moeseprints.incois.gov.in/id/eprint/1450

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