a numerical analysis of laminar forced convection and entropy generation of a diamond-fe3o4/water hybrid nanofluid in a rectangular minichannel

The convective heat transfer and entropy generation of diamond-fe3o4/water hybrid nanofluid through a rectangular minichannel is numerically investigated under laminar flow conditions. nanoparticle volume fractions for diamondfe3o4/water hybrid nanofluid are in the range 0.05-0.20% and reynolds number varies from 100 to 1000. the finite volume method is used in the numerical computation. the results obtained for diamond-fe3o4/water hybrid nanofluid are compared with those of diamond/water and fe3o4/water conventional nanofluids. it is found that 0.2% diamond-fe3o4 hybrid nanoparticle addition to pure water provides convective heat transfer coefficient enhancement of 29.96%, at re=1000. the results show that diamond-fe3o4/water hybrid nanofluid has higher convective heat transfer coefficient and nusselt number when compared with diamond/water and fe3o4/water conventional nanofluids. for diamond-fe3o4/water hybrid nanofluid, until re=600, the lowest total entropy generation rate values are obtained for 0.20% nanoparticle volume fraction. however, after re=800, diamond-fe3o4/water hybrid nanofluid with 0.20% 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 fe3o4/water conventional nanofluids. for 0.2% nanoparticle volume fraction, diamond-fe3o4/water hybrid nanofluid and diamond/water nanofluid have their minimum entropy generation rate at re=500 and at re=900, respectively. moreover, this minimum entropy generation rate point changes with nanoparticle volume fraction values of nanofluids.