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An Experimental Study on the Effects of Porous Layer Treatment on Evaporative Cooling of an Inclined Surface  

Lee Dae Young (Thermal/Flow Control of Research Center, Korea Institute of Science and Technology)
Lee Jae Wan (Graduate School of Mechanical Engineering, Kookmin University)
Kang Byung Ha (School of Mechanical and automotive Engineering, Kookmin University)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.17, no.1, 2005 , pp. 25-32 More about this Journal
Abstract
Falling film heat transfer has been widely used in many applications in which heat and mass transfer occur simultaneously, such as evaporative coolers, cooling towers, absorption chillers, etc. In such cases, it is desirable that the falling film spreads widely on the surface forming thin liquid film to enlarge contact surface and to reduce the thermal resistance across the film and/or the flow resistance to the vapor stream over the film. In this work, the surface is treated to have thin porous layer on the surface. With this treatment, the liquid can be spread widely on the surface by the capillary force resulting from the porous structure. In addition to this, the liquid can be held within the porous structure to improve surface wettedness regardless of the surface inclination. The experiment on the evaporative cooling of an inclined surface has been conducted to verify the effectiveness of the surface treatment. It is measured that the evaporative heat transfer increases about $50\%$ by the porous layer treatment as compared with that from orignal bare surfaces.
Keywords
Evaporation heat transfer; Surface Characteristics; Wettedness; Porous layer; Inclined surface;
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  • Reference
1 Kim, N. H., 1998, Enhancement of thin film evaporation on low-fin tubes, Korean J. Air-Conditioning Refrig. Engineering. Vol. 10, No. 6, pp. 674-682
2 Kim, H .Y. and Kang, B. H., 2003, Effects of hydrophilic surface treatment on eva- poration heat transfer at the outside wall of horizontal tubes, Applied Thermal Eng- ineering, Vol. 23, pp. 449-458   DOI   ScienceOn
3 Schmuki, P. and Laso, M., 1990, On stability of rivulet flow, J. Fluid Mech., Vol. 215, pp. 125-143   DOI
4 Yan, W. M. and Soong, C. Y., 1995, Convective heat and mass transfer along an inclined heated plate with film evaporation, Int. J. of Heat Mass Transfer, Vol. 38, No. 7, pp. 1261-1269   DOI   ScienceOn
5 Wang, T. A. and Reid, R. L., 1996, Surface wettability effect on an indirect evaporative cooling system, ASHRAE Transactions, Vol. 102, No. 1, pp. 427-433
6 Zheng, G. S. and Worek, W. M., 1996, Method of heat and mass transfer enhance- ment in film evaporation, Int. J. Heat Mass Transfer, Vol. 39, No. 1, pp. 97-108   DOI   ScienceOn
7 Karapantsios, T. D. and Karabelas, A. J., 1995, Longitudinal characteristics of wavy falling films, Int. J. Multiphase Flow, Vol. 21, No. 1, pp. 119-127   DOI   ScienceOn