Laminar Forced Convective Heat Transfer Performance Analysis of Elliptical and Semicircular Microchannels

In this paper, a single-phase fluid flow, and heat transfer characteristics of elliptical and semicircular microchannels using air as a working fluid are analyzed for a range of Reynolds number (130 <= Re <= 470). Experiments are performed on aluminum alloy (AlSi10Mg) microchannels, including inlet and outlet manifolds fabricated using three-dimensional printing technology. A numerical model is developed and validated with the experimental results to study the effect of operating and geometrical parameters on the heat transfer performance of the microchannels. It is found that the temperature difference, Poiseuille number, and average Nusselt number in the elliptical microchannel are higher for all the Reynolds numbers. The axial wall conduction significantly affects the temperature distribution in the fluid and wall of the microchannels. The effect of axial conduction weakens with the increase in the Reynolds number. The numerical average Nusselt number increases with Reynolds number for Re > 150 and is higher than the average Nusselt number predicted from the correlation.