Enhanced convection in mini channel with CNT fins

Abstract

Thermal performance can be improved by modifying the walls of a rectangular minichannel with micro-fins of bundles of ideal single-wall carbon nanotubes (SWCNTs) (circle, square, rectangle, triangle and hexagon) and using a nanofluid. A staggered array yields better thermal performance than an inline array as either a solid or porous medium. The thermal effects with SWCNTs were better than multiwalled carbon nanotubes. Fins as porous media for SWCNTs resulted in heat transfer that was 5% (maximum) greater than solid media. A staggered triangle array yielded better thermal performance as a solid (82%) or porous medium (92%) than an unfinned array. On a minichannel, with or without nanotubes and uniform coating, nanofluid increased the thermal performance with the best performance by CuO/H2O. Thermal enhancement of 226% was obtained using staggered triangular fins with a larger fin height of 0.75 mm, smaller fin width of 0.5 mm, spacing the fins at double the fin width, and 0.01% CuO/H2O nanofluid. The corresponding friction factor differential was found to be 625%.

Keywords

• mini-channels
• nanofluid
• nanotube fin
• pressure drop
• thermal performance