Digital Interferometric Measurement of Forced Convection Heat Transfer in a Miniature Rectangular Channel

Investigations have been performed on convective heat transfer in water flowing through mini-channels using the non intrusive technique of laser interferometry coupled with digital image processing. Optical glass channels, fabricated with metallic heating surfaces, were studied using a Mach-Zehnder interferometer configuration. Fringe patterns captured using a high-sensitivity CCD camera were analyzed digitally based on a calculation method developed for the liquid medium. Results of parametric studies were compared and contrasted with relevant theoretical solutions from the literature. Indication of the onset of turbulence at Reynolds numbers smaller than the conventional transition Reynolds number for large channels has also been noticed in the experimental investigation.