Mixed Convection in a Vertical Microannulus Between Two Concentric Microtubes


Avci M., AYDIN O.

JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME, vol.131, no.1, 2009 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 131 Issue: 1
  • Publication Date: 2009
  • Doi Number: 10.1115/1.2977552
  • Journal Name: JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Keywords: microfluidics, vertical microannulus, mixed convection, temperature jump, velocity slip, LAMINAR FORCED-CONVECTION, HEAT-CONDUCTION MODEL, NATURAL-CONVECTION, FLUID-FLOW, SLIP-FLOW, MICROCHANNEL, ANNULUS

Abstract

In this study, fully developed mixed convective heat transfer of a Newtonian fluid in a vertical microannulus between two concentric microtubes is analytically investigated by taking the velocity slip and the temperature jump at the wall into account. The effects of the mixed convection parameter Gr/Re, the Knudsen number Kn, and the aspect ratio r(*) on the microchannel hydrodynamic and thermal behaviors are determined. Finally, a Nu=f(Gr/Re,Kn,r(*)) expression is developed. It is disclosed that increasing Gr/Re enhances heat transfer while rarefaction effects considered by the velocity slip and the temperature jump in the slip flow regime decreases it. [DOI: 10.1115/1.2977552]