کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
669379 | 1458746 | 2014 | 19 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Channel aspect ratio effect on thermal performance of air-water slug flow through U-bend channels
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
جریان سیال و فرایندهای انتقال
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چکیده انگلیسی
This study investigates the effect of channel height-to-width ratio (Aspect Ratio, AR) on heat-transfer rates, pressure-drop coefficients (f) and thermal performances of air-water flows through horizontal and vertical U-bend rectangular channels at intermittent slug and slug-annular flow conditions. Interfacial two-phase flow structures, local and area-averaged Nusselt numbers (Nu), f coefficients, channel-wise averaged void fractions (α) and thermal performance factors (TPF) for three sets of horizontal and vertical U-bend channels of AR = 1, 0.83 and 0.33 are measured with liquid Reynolds numbers (ReL) and air-to-water mass flow ratios (AW) in the range of 1500 â¤Â Re â¤Â 10000 and 0 â¤Â AWâ¤0.024. Early transitions from slug flow to slug-annual flow along with the shortened air slug and the extended period of the trailing-edge bubbly flow over each intermittent cycle are promoted by decreasing AR to elevate both heat transfer rates and pressure drops for the U-bend channels with small AR. A set of selective Nu, f and TPF data illustrates the interdependency between Nu, f, TPF and the air-water flow structures in present test channels with different AR. The area averaged endwall Nu for each U-bend test channel (Nu¯) and the corresponding f and TPF are cross-examined to generate a set of heat-transfer and pressure-drop correlations, which permit the evaluations of isolated and interdependent ReL, AW and AR effects on Nu¯ and f, to assist various design applications.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Thermal Sciences - Volume 76, February 2014, Pages 11-29
Journal: International Journal of Thermal Sciences - Volume 76, February 2014, Pages 11-29
نویسندگان
Shyy Woei Chang, Kuei Feng Chiang, Ching Yuan Lin,