Low Reynolds numbers convective heat transfer enhancement in roughened microchannels

• Published in: International communications in heat and mass transfer 2020-03, Vol.112, p.104486, Article 104486
• Main Authors: Hsieh, Shou-Shing, Hsieh, Yu-Cheng, Hsu, Ya-Chiao, Huang, Ching-Feng
• Format: Article
• Language: English
• Subjects: Axial wall heat conduction; Convective microchannel flow; Heat transfer enhancement; Pin-fin roughened surface
• ISSN: 0735-1933; 1879-0178
• DOI: 10.1016/j.icheatmasstransfer.2020.104486

Heat transfer enhancement studies were conducted on a variety of roughened microchannels for a laminar flow at 3≦Re≦25 with DI water as the cooling fluid. Five different discrete roughened surfaces, which were circular, square, triangular, elliptical, and hexagonal in shape, were used in the test channels with a channel cross-sectional area aspect (height to width) ratio of 0.25. The smooth-surface channel had a length of 30 cm, width of 200 μm, and height of 50 μm, which creates the hydraulic diameter of 80 μm for the study. A constant heat flux of 1.25 W/cm2 was applied to the bottom of the channel through the ITO surface. Results of the cooling performance in terms of the enhancement factor compared to those of a smooth channel found that the square pin-fin roughened surfaces had the best transfer enhancement followed by the ellipse, circle, hexagon, and triangle as compared to that of a smooth surface. Furthermore, axial wall heat conduction was noted for both smooth and roughened channels. •Convective heat transfer enhancement in five different roughened microchannels.•Exploring the phenomenon of conjugate heat transfer in microchannels.•Heat transfer enhancement effect of microchannels at low Reynolds number.