Comparative investigation of convective heat transfer and pressure drop characteristics of MWCNT, Fe3O4, and MWCNT/Fe3O4 nanofluids

Abstract

The present work discusses the experimental investigation of the convective heat transfer (CHT) and pressure drop characteristics of a hybrid nanofluid (HNF). The multi-walled carbon nanotube (MWCNT) NF, Fe3O4 NF, and MWCNT/Fe3O4 HNFs with 0.025 wt% to 0.2 wt% concentrations were prepared through ultrasonic dispersion. The CHT coefficient of the three NFs was investigated in a cylindrical test section at different Reynolds numbers (Re) and compared. As an outcome, the CHT coefficients of the MWCNT/Fe3O4 HNFs ranged from 1823.2 to 2030.5 W/m2·K, which is 6%–15.9% more than the base fluid. Furthermore, the MWCNT/Fe3O4 HNFs outperformed the MWCNT and Fe3O4 NFs individually during the CHT coefficient enhancement. At Re of 1000–1600, the increase in pressure drop of the MWCNT NF, Fe3O4 NF, and MWCNT/Fe3O4 HNFs varied from 62.4% to 91.7% as compared to water. Therefore, it is expected that the MWCNT/Fe3O4 HNF could be an effective heat transport medium.

Keywords

• Convective heat transfer
• Thermal conductivity
• Viscosity
• Hybrid nanofluid
• Multi-walled carbon nanotube
• Pressure drop