An Experimental Study of the Effect of High Electric Field on Mass Transfer Enhancement

Document Type : Research Paper

Authors

Development and Optimization of Energy Technologies Research Division, Research Institute of Petroleum Industry (RIPI)

Abstract

Applying corona wind as a novel technique can lead to a great level of heat and mass transfer augmentation by using a very small amount of energy. The enhancement of forced flow evaporation rate by applying electric field (corona wind) has been experimentally evaluated in this study. Corona wind produced by a fine wire electrode charged with positive high DC voltage impinges on water surface and leads to an evaporation enhancement by disturbing the saturated air layer over water surface. The study was focused on the effect of corona wind velocity, electrode spacing, and air flow velocity on the level of the evaporation enhancement. Two sets of experiments, i.e. with and without electric field, have been conducted. The data obtained from the first experiment were used as a reference for the evaluation of the evaporation enhancement in the presence of electric field. The applied voltages ranged from corona threshold voltage to spark over voltage with increments of 1 kV. The results shows that corona wind has a great enhancement effect on water evaporation rate, but its effectiveness gradually diminishes by increasing air flow velocity. The maximum enhancements are 7.3 and 3.6 times for air velocities of 0.125 and 1.75 m.s-1 respectively.
 

Keywords


 
[1]. Laohalertdechaa S., Naphonb P., and Wongwises S., “A Review of Electrohydrodynamic Enhancement of Heat Transfer”, Renewable and Sustainable Energy Review, Vol. 11, pp. 858–876, 2007.
[2]. Molki M., and Bhamidipati K., “Enhancement of Convective Heat Transfer in the Developing Region of Circular Tubes Using Corona Wind”, International Journal of Heat and Mass Transfer, Vol. 47, pp. 4301–4314, 2004.
[3]. Sadek H., Robinson A. J., Cotton J. S., Ching C. Y.,  and Shoukri M., “Electrohydrodynamic Enhancement of In-tube Convective Condensation Heat Transfer”, International Journal of Heat and Mass Transfer, Vol. 49, pp. 1647–1657, 2006.
[4]. Alemrajabi A., and Lai F. C., “EHD-enhanced Drying of Partially Wetted Glass Beads”, Drying Technology, Vol. 23, pp. 597–609, 2005.
[5]. Goodenough T. I. J., Goodenough P. W., and Goodenough S. M. “The Efficiency of Corona Wind Drying and its Application to the Food Industry”, Journal of food Engineering, Vol. 80, pp. 1233-1238, 2007.
[6]. Lai F. C., Huang M., and Wong D. S., “EHD-Enhanced Water Evaporation”, Drying Technology, Vol. 22, pp. 595–606, 2004.
[7]. Lai, F. C., and Sharma, R. K., “EHD-enhanced Drying with Multiple Needle Electrodes”, Journal of Electrostatics, Vol. 63, pp. 223–237, 2005.
[8]. Chen Y. H., and Barthakur N. N., “Electrohydrody namic Drying of Potato Slabs”, Journal of Food Engineering, Vol. 23, pp. 107–119, 1994.
[9]. Barthakur N.N., “Electrohydrodynamic Enhancement of Evaporation from NaCl Solutions”, Desalination, Vol. 78, pp. 455–465, 1990.
[10]. Shakouri Pour M., and Esmaeilzadeh E., “Experimental Investigation of Convective Heat Transfer Enhancement from 3D-shape Heat Sources by EHD Actuator in Duct Flow”, Experimental Thermal and Fluid Science, Vol. 35, pp. 1838–1891, 2011.
[11]. Atalık K., and Sِnmezler U., “Heat Transfer Enhancement for Boundary Layer Flow over a Wedge by the Use of Electric Fields”, Applied Mathematical Modeling, Vol. 35, pp. 4516–4525, 2011.
[12]. Rashkovan A., Sher E., and Kalman, H. “Experimental Optimization of an Electric Blower by Corona Wind”, Applied Thermal Engineering, Vol. 22, 1587–1599, 2002.
[13]. Stuetzer M., “Ion Drag Presuure Generation”, Journal of Applied Physics, Vol. 30, pp. 984-994, 1959.
[14]. Kamkari B. Experimental Investigation of Water Evaporation Enhancement Using Electrohydrodynamics, M.Sc. Thesis, Department of Mechanical Engineering, Isfahan University of Technology, 2008.
[15]. Sadek, S., Fax, E., Hurwitz, M., “The Influence of Electric Fields on Convective Heat and Mass Transfer from a Horizontal Surface under Force Convection”, Journal of Heat Transfer, Vol. 94, pp. 144-148, 1972.