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Proceedings Paper

Experimental investigation of flow and heat transfer characteristics of R-134a in microchannels
Author(s): Hisham E. Hegab; Abdullahel Bari; Timothy A. Ameel
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Paper Abstract

Fluid flow and heat transfer characteristics of single-phase flows in microchannels for refrigerant R-134a were experimentally investigated. Experiments were conducted using rectangular channels micro-milled in aluminum with hydraulic diameters ranging from approximately 112-mm to 210-mm and aspect ratios that varied from 1.0 to 1.5. Using overall temperature, flow rate, and pressure drop measurements, friction factors and convective heat transfer coefficients were experimentally determined for steady flow conditions. Reynolds number, relative roughness, and channel aspect ratio were the parameters examined in predicting friction factor and Nusselt number for the experiments. Experiment results indicated transition from laminar to turbulent flow occurred between a Reynolds number of 2,000-4,000. Friction factor results were consistently lower than values predicted by macroscale correlations. Nusselt number results indicated channel size may suppress turbulent convective heat transfer. Results also indicate that surface roughness may affect heat transfer characteristics in the turbulent regime.

Paper Details

Date Published: 28 September 2001
PDF: 9 pages
Proc. SPIE 4560, Microfluidics and BioMEMS, (28 September 2001); doi: 10.1117/12.443049
Show Author Affiliations
Hisham E. Hegab, Louisiana Tech Univ. (United States)
Abdullahel Bari, Dutchess Community College (United States)
Timothy A. Ameel, Univ. of Utah (United States)


Published in SPIE Proceedings Vol. 4560:
Microfluidics and BioMEMS
Carlos H. Mastrangelo; Holger Becker, Editor(s)

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