Augmentation of heat transfer in a microtube and a wavy microchannel using hybrid nanofluid: A numerical investigation

Abstract

The paper discusses the numerical investigation involving forced convective heat transfer (HT) in the laminar flow regime is carried out for nanofluid (NF) and hybrid NF (HNF) in a microtube and wavy microchannel. Water-based Al2O3 NF and water-based Al2O3-Ag HNF is studied for this purpose. Reynolds number (Re), temperature, volume fraction, and nanoparticle (NP) size are varied for the analysis at a constant HT rate. Numerical results characterizing the performances of NF and HNF are presented in terms of the local HT coefficient. It is found that with the increase in Reynolds number, volume fraction, and temperature, local HT coefficient is increased. For Reynolds number of 50 and 𝜑 = 3%, a maximum of 11.03% increase in HT coefficient is obtained for microtube, while for the same case, a maximum of 10.16% is found for wavy microchannel. Comparison of NF and HNF reveals superior HT property of the later. However, microtube exhibits better HT coefficient than the wavy channel at constant heat flux, length, and area.