Library Subscription: Guest
Home Archives Thermal Letter Officers Future meetings Assembly for International Heat Transfer Conferences
International Heat Transfer Conference 16

ISSN: 2377-424X (online)
ISSN: 2377-4371 (flashdrive)

CONTROL OF POOL BOILING HYDRODYNAMICS THROUGH SURFACE WETTABILITY PATTERNING

Taylor P. Allred
School of Mechanical Engineering, Purdue University, 585 Purdue Mall, 47907-2088, West Lafayette, IN, USA

Justin A. Weibel
School of Mechanical Engineering, Purdue University, 585 Purdue Mall, 47907-2088, West Lafayette, IN, USA

Suresh V. Garimella
NSF Cooling Technologies Research Center, School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907-2088 USA

DOI: 10.1615/IHTC16.bae.022684
pages 739-746


KEY WORDS: Boiling and evaporation, Thermal management, Heat transfer enhancement, Electronic equipment cooling

Abstract

Boiling surface enhancements including engineered wettability, porous coatings, and other geometric modifications have long been explored to meet increasing heat dissipation requirements. Recent investigation of the effects of biphilic surfaces, i.e., those with intermixed wetting and non-wetting regions, on pool boiling heat transfer have indicated potential enhancements of both the boiling heat transfer coefficient and the critical heat flux (CHF) compared to a uniform hydrophilic surface. There is no unified explanation for the CHF enhancement mechanism on biphilic surfaces, which does not follow the accepted understanding of the effects of uniform surface wettability on CHF and boiling hydrodynamics. In this study, we fabricate biphilic surfaces with the goal of controlling liquid-vapor hydrodynamics, as a potential enhancement mechanism. The surfaces feature alternating superhydrophobic and hydrophilic stripes of equal width. The stripe widths differ from surface to surface while the total area of each wettability type is maintained at 50% each, to identify the impact of this stripe width on the boiling behavior. Unlike prior studies, the superhydrophobic surface texture is infiltrated with liquid prior to boiling, i.e., brought into an initial Wenzel state. Nucleate boiling from this initial state prevents vapor bubbles from spreading over these regions and enables large superhydrophobic areas to be incorporated without detrimental effects on CHF. Nucleation preferentially occurs on the superhydrophobic regions, allowing control of the hydrodynamics via the surface wettability patterning. The heat transfer coefficient and CHF improve as the stripe width decreases under this mode of boiling; the possible mechanisms of enhancement on biphilic surfaces are discussed based on evaluation of prevailing theories.

Purchase $25.00 Check subscription Publication Ethics and Malpractice Recommend to my Librarian Bookmark this Page