Vol. 40, No. 2 (2017) (17)

Nanotube Fins on Mini-channel Walls and Nanofluids for Thermal Enhancement

K. S. Arjun & K. Rakesh

K. S. Arjun & K. Rakesh, Nanotube Fins on Mini-channel Walls and Nanofluids for Thermal  Enhancement, Journal of Mechanical Engineering Research and Developments, vol. 40, no. 2, pp. 317-327, 2017.

ABSTRACT: The thermal performance could be improved by modifying the walls of the rectangular mini channel with micro fins of bundles of ideal single walled carbon nanotubes (circle, square, rectangle, triangle and hexagon) and using nanofluid. It was observed that on a mini channel surface with or without nanotubes and uniform coating; the nanofluid increases the thermal performance with the best performance by CuO/H2O nanofluid. Thermal performance enhancement of 226% was obtained by using staggered triangular fins with larger fin height of 0.75 mm, smaller fin width of 0.5 mm and spacing double the fin width and 0.01% CuO/H2O nanofluid. The corresponding pressure drop differential was found to be 475%. Staggered array yields better thermal performance than inline configuration both as solid and porous medium, with the best being latter medium. Staggered triangle array yields better thermal performance as both solid (82%) and porous medium (92%), in comparison to the unfinned. The thermal effects with single walled nanotubes of Carbon were better in relation to multi-walled nanotubes. Fins with SWCNTs when modeled as a porous media increased the heat transfer performance significantly with highest value of 5% for SWCNTs in comparison to solid medium.

Keywords: Mini-channels; Nanofluid; Nanotube fin; Thermal performance.