A Numerical Analysis of Laminar Forced Convection and Entropy Generation of a Diamond-Fe۳O۴/Water Hybrid Nanofluid in a Rectangular Minichannel

The convective heat transfer and entropy generation of diamond-Fe۳O۴/water hybrid nanofluid through a rectangular minichannel is numerically investigated under laminar flow conditions. Nanoparticle volume fractions for diamond-Fe۳O۴/water hybrid nanofluid are in the range ۰.۰۵-۰.۲۰% and Reynolds number varies from ۱۰۰ to ۱۰۰۰. The finite volume method is used in the numerical computation. The results obtained for diamond-Fe۳O۴/water hybrid nanofluid are compared with those of diamond/water and Fe۳O۴/water conventional nanofluids. It is found that ۰.۲% diamond-Fe۳O۴ hybrid nanoparticle addition to pure water provides convective heat transfer coefficient enhancement of ۲۹.۹۶%, at Re=۱۰۰۰. The results show that diamond-Fe۳O۴/water hybrid nanofluid has higher convective heat transfer coefficient and Nusselt number when compared with diamond/water and Fe۳O۴/water conventional nanofluids. For diamond-Fe۳O۴/water hybrid nanofluid, until Re=۶۰۰, the lowest total entropy generation rate values are obtained for ۰.۲۰% nanoparticle volume fraction. However, after Re=۸۰۰, diamond-Fe۳O۴/water hybrid nanofluid with ۰.۲۰% nanoparticle volume fraction has the highest total entropy generation rate compared to other nanoparticle volume fractions. A similar pattern emerges from the comparison with diamond/water and Fe۳O۴/water conventional nanofluids. For ۰.۲% nanoparticle volume fraction, diamond-Fe۳O۴/water hybrid nanofluid and diamond/water nanofluid have their minimum entropy generation rate at Re=۵۰۰ and at Re=۹۰۰, respectively. Moreover, this minimum entropy generation rate point changes with nanoparticle volume fraction values of nanofluids.

کلیدواژه ها:

Bejan number ، Convective heat transfer ، Hybrid nanofluid ، Entropy generation ، Minichannel