An experimental comparison of convective heat transfer and friction factor of Al2O3 nanofluids in a tube with and without butterfly tube inserts

Azari A., Derakhshandeh M.

Journal of the Taiwan Institute of Chemical Engineers, vol.52, pp.31-39, 2015 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 52
  • Publication Date: 2015
  • Doi Number: 10.1016/j.jtice.2015.02.009
  • Journal Name: Journal of the Taiwan Institute of Chemical Engineers
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.31-39
  • Keywords: Convection, Heat transfer, Nusselt number, Butterfly tube insert, Nanofluid, Nanoparticle, AQUEOUS SUSPENSIONS, THERMAL-CONDUCTIVITY, CIRCULAR TUBE, FLOW BEHAVIOR, SINGLE-PHASE, TAPE INSERTS, ENHANCEMENT, PERFORMANCE, EXCHANGER, PIPE
  • Anadolu University Affiliated: Yes

Abstract

© 2015 Taiwan Institute of Chemical Engineers.Nanofluids have acquired comprehensive attention due to their role in enhancing the efficiency of thermal systems. The present study reports a further enhancement in Nusselt number along with the modification of flow system structures, namely, the addition of butterfly tube inserts (BTI) with an inclined angle of 90° in a tube at constant heat flux conditions. Experiments are performed to determine Nusselt number and the friction factor of Al2O3/water nanofluid up to 2.5% nanoparticle volume concentration (NVC) and in the Reynolds number range of 750-8500. Results showed that by using BTI, nanofluids friction factor increased by an average 2.6% relative to the plain tube. Also, Nusselt number increased with Reynolds and along the tube axis for laminar regime. A considerable enhancement of about 345% in the Nusselt was observed at 0.027% NVC and Re=1500 for the flow in a tube with its BTI relative to plain tube (PT). A 2.5% increase in the NVC decreased Nusselt number for the flow in a tube with BTI. Finally, two correlations for the friction factor and Nusselt number of water and alumina nanofluid in a tube with BTI based on the measured experimental values were developed.