Enhancement of Hydrophilic Characteristics of Non-Wetting Porous Substrates by Kaolinite TreatmentThe use of porous media has enormous potential for thermal management and phase separation in terrestrial, micro, Lunar and Marian gravity environments. Recently, a porous media based gravity insensitive condensing heat exchanger for humidity control has been proposed and successfully demonstrated by the authors. A strongly hydrophilic porous substrate is essential for condensing and trapping water vapor from the airstreams. However, most porous media which have good thermal characteristics are poorly wetting to water. This poses a significant obstacle in the development of the porous media based condensing heat exchanger. In response to this problem, a clay based process was developed for improving the wettability of non-wetting and partially wetting porous media. It was demonstrated that poorly wetting porous graphite as well as porous stainless steel could be converted to a completely wetting porous substrate by kaolinite treatment. The process enhances the wettability of both the surface and the interior pores. The paper presents experimental results of enhanced wettability of the treated substrate in terms of imbibition rate and capillary pressure as a function of saturation. The long term stability of the treated surface is also investigated and discussed.
Document ID
20070031803
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Khan, Lutful I. (Cleveland State Univ. Cleveland, OH, United States)
Hasan, Mohammad M. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 23, 2013
Publication Date
July 9, 2007
Subject Category
Composite Materials
Report/Patent Number
2007-01-3178E-16235
Meeting Information
Meeting: International Conference on Environmental Systems