TY - GEN
T1 - Visualization of boiling heat transfer on micro porous coated surface in confined space
AU - Yang, Chien Yuh
AU - Liu, Chien Fu
PY - 2013
Y1 - 2013
N2 - Numerous researches have been developed for pool boiling on microporous coated surface in the past decade. The nucleate boiling heat transfer was found to be increased by up to 4.5 times than that on uncoated surface. Recently, the two-phase micro heat exchangers have been considered for high flux electronic devices cooling. The enhancement techniques for improving the nucleate boiling heat transfer performance in the micro heat exchangers have gotten more importance. Previous studies of microporous coatings, however, have been restricted to boiling in unconfined space. No studies have been made on the feasibility of using microporous coatings for enhancing boiling in confined spaces. This study provides an experimental observation of the vapor generation and leaving processes on microporous coatings surface in a 1-mm confined space. It would be helpful for understanding the mechanism of boiling heat transfer and improving the design of two-phase micro heat exchangers. Aluminum particles of average diameter 20 um were mixed with a binder and a carrier to develop a 150 um thickness boiling enhancement paint on a 3.0 cm by 3.0 cm copper heating surface. The heating surface was covered by a thin glass plate with a 1 mm spacer to form a 1 mm vertical narrow space for the test section. The boiling phenomenon was recorded by a high speed camera. In addition to the three boiling regimes observed by Bonjour and Lallemand [1], i.e., isolated deformed bubbles, coalesced bubbles and partial dryout at low, moderate and high heat fluxes respectively in unconfined space, a suction and blowing process was observed at the highest heat flux condition. Owing to the space confinement, liquid was sucked and vapor was expelled periodically during the bubble generation process. This mechanism significantly enhanced the boiling heat transfer performance in confined space.
AB - Numerous researches have been developed for pool boiling on microporous coated surface in the past decade. The nucleate boiling heat transfer was found to be increased by up to 4.5 times than that on uncoated surface. Recently, the two-phase micro heat exchangers have been considered for high flux electronic devices cooling. The enhancement techniques for improving the nucleate boiling heat transfer performance in the micro heat exchangers have gotten more importance. Previous studies of microporous coatings, however, have been restricted to boiling in unconfined space. No studies have been made on the feasibility of using microporous coatings for enhancing boiling in confined spaces. This study provides an experimental observation of the vapor generation and leaving processes on microporous coatings surface in a 1-mm confined space. It would be helpful for understanding the mechanism of boiling heat transfer and improving the design of two-phase micro heat exchangers. Aluminum particles of average diameter 20 um were mixed with a binder and a carrier to develop a 150 um thickness boiling enhancement paint on a 3.0 cm by 3.0 cm copper heating surface. The heating surface was covered by a thin glass plate with a 1 mm spacer to form a 1 mm vertical narrow space for the test section. The boiling phenomenon was recorded by a high speed camera. In addition to the three boiling regimes observed by Bonjour and Lallemand [1], i.e., isolated deformed bubbles, coalesced bubbles and partial dryout at low, moderate and high heat fluxes respectively in unconfined space, a suction and blowing process was observed at the highest heat flux condition. Owing to the space confinement, liquid was sucked and vapor was expelled periodically during the bubble generation process. This mechanism significantly enhanced the boiling heat transfer performance in confined space.
UR - http://www.scopus.com/inward/record.url?scp=84892638354&partnerID=8YFLogxK
U2 - 10.1115/ICNMM2013-73175
DO - 10.1115/ICNMM2013-73175
M3 - 會議論文篇章
AN - SCOPUS:84892638354
SN - 9780791855591
T3 - ASME 2013 11th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM 2013
BT - ASME 2013 11th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM 2013
T2 - ASME 2013 11th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM 2013
Y2 - 16 June 2013 through 19 June 2013
ER -