Experimental and numerical study of drag reduction and heat transfer enhancement in a vertical pipe using water/polyisobutylene/nano-SiO₂ polynanofluids

Abstract

Poly-nanofluids (PNFs) are a new type of material that is manufactured by dispersing nanoparticles in dilute polymer solutions. This study looked at heat transfer and drag reduction using a water/polyisobutylene/nano-SiO₂ PNF through a vertical copper pipe under conditions of constant heat flux. The effects of ploy-isobutylene (PIB) polymer solution, water/nano-SiO₂ nanofluid, and aqueous PNF on heat transfer and drag reduction in a vertical pipe have been studied, separately. All prepared solutions had Reynolds numbers ranging from 7000 to 22000. Nano-SiO₂ particles with an average size 20 nm and concentration ranges of 0.1–1 wt.% have been dispersed in aqueous PIB solutions as base fluids with 10–50 ppm concentration of the polymer. The optimal nanoparticle and polymer concentrations for the prepared nanofluid, polymer solution, and PNFs were 0.75 wt.% and 50 ppm, respectively. The friction factor of PNFs at optimal concentrations was 75% less than pure water. Ansys Fluent software was employed to verify the findings of the experiment and simulate the heat transfer and drag reduction phenomena at optimal conditions. Based on the results, the experimental and numerical data were in reasonable agreement, with a deviation of less than 5%.

Graphical Abstract

Keywords:

• Experimental
• simulation
• drag reduction
• heat transfer
• vertical pipe
• water/PIB/nano-SiO₂ PNFs