Experimental investigation on the effects of bifurcation angle on enhanced microscale heat transfer in macro geometry
Foo, Zi Hao
Cheng, Kai Xian
Ooi, Kim Tiow
Date of Issue2016
International Conference on Mechanical, Industrial and Power Engineering (1st:2016:Tokyo,Japan)
School of Mechanical and Aerospace Engineering
The effectiveness of microscale heat transfer in macro geometry has been demonstrated to produce comparable heat transfer performance to that of conventional microchannels. For this research, a microchannel was created by fitting an insert with nominal diameter 19.4 mm concentrically within a hollow cylinder with inner diameter 20.0 mm, thereby producing a microchannel with an annular gap of 300 µm. Surface profiles on the insert were optimised to recover pressure loss, aiming to address the increased pumping requirements that accompany the improvement in heat transfer capabilities. A bifurcation angle was incorporated into the offset fin geometry design. The increased heat removal capability at the same pumping power and the reduction of pumping power for the same heat removal duty for three different bifurcation angles, namely 70, 75 and 80 degrees, were investigated with respect to parallel channels. The experimental study was conducted at a constant heat flux of 500 W at Reynolds number ranging from 690 to 4600. The amount of fluid in the microchannel, heat transfer area, rate of heat supplied, average channel gap size, channel length and fin height were kept constant. Experimental results successfully validated the effectiveness of bifurcation angles in the recovery of pressure loss across the microchannel. As compared to parallel channels, the 80-degrees bifurcating fins displayed the highest enhancement of the heat transfer coefficient and greatest reduction of the pumping power, which are 27% enhanced and 52% reduced respectively, at a given heat removal duty.
© 2016 The Author(s) (International Conference on Mechanical, Industrial and Power Engineering (1st:2016:Tokyo,Japan)). This is the author created version of a work that has been peer reviewed and accepted for publication by International Conference on Mechanical, Industrial and Power Engineering (1st:2016:Tokyo,Japan). It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document.