surface tension;
open microchannel;
turning angle;
head loss coefficient;
aspect ratio;
D O I:
10.1007/s10404-007-0237-5
中图分类号:
TB3 [工程材料学];
学科分类号:
0805 ;
080502 ;
摘要:
Present study examines the flow characteristics of open microchannels with sharp turns by experimental and numerical methods. For the open channel system in microscale, the flow is mainly driven by surface tension at atmospheric pressure. The open channels are of various aspect ratios of depth-to-width, ranging from 0.75 to 3, and of turning angles from 45 degrees to 135 degrees. It is found that the turning angle and the aspect ratio of depth-to-width play major roles in the velocity of liquid front advancing, the meniscus of liquid-gas interface shape, and head loss of flow due to turning. Besides, the radius of curvature of the liquid front is reduced as the liquid front travels downstream and over the turning elbow. The loss coefficient remains the same for turning angles less than 75 degrees, whereas it is increased further and is even more pronounced for turning angles larger than 105 degrees. Numerical predications based on conservation laws agree with the experimental observations, and the flow characteristics are well described for open channel in microscale, as the aspect ratio is greater than or near to 1.5.
机构:Hong Kong Univ Sci & Technol, Dept Engn Mech, Kowloon, Hong Kong, Peoples R China
Wu, HY
;
Cheng, P
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机构:
Hong Kong Univ Sci & Technol, Dept Engn Mech, Kowloon, Hong Kong, Peoples R ChinaHong Kong Univ Sci & Technol, Dept Engn Mech, Kowloon, Hong Kong, Peoples R China
机构:Hong Kong Univ Sci & Technol, Dept Engn Mech, Kowloon, Hong Kong, Peoples R China
Wu, HY
;
Cheng, P
论文数: 0引用数: 0
h-index: 0
机构:
Hong Kong Univ Sci & Technol, Dept Engn Mech, Kowloon, Hong Kong, Peoples R ChinaHong Kong Univ Sci & Technol, Dept Engn Mech, Kowloon, Hong Kong, Peoples R China