Numerical investigation in comparing the influence of water-silver-magnesium oxide hybrid nanofluid and water-silver normal nanofluid on fluid flow, heat transfer and entropy generation in an enclosure with rotating heat sources

Hybrid nanofluids are made of a base fluid and at least two different types of nanoparticles. The main purpose of using hybrid nanofluids is that they have better thermophysical properties comparing to that of nanofluids with single nanoparticles. In this paper, a comparison between water-silver-magnesium oxide hybrid nanofluid and water-silver nanofluid's influence on the flow field, heat transfer and entropy generation in an enclosure with rotating heat sources have been investigated. The study has been done for a Grashof number of 10(4), a Richardson number from 0.3 to 100 and for volume fractions of 0 to 0.01 of nanoparticles. The governing equations are solved numerically using the finite volume method and the SIMPLER algorithm with a computer program using FORTRAN programming language. The results show that in all of Richardson numbers with the increment in volume fraction of nanoparticles, the maximum size of the flow function has been reduced. For all of the investigated Richardson numbers and water-silver nanofluid and water-silver-magnesium oxide hybrid nanofluid with an increment in volume fraction of nanoparticles, the maximum size of the flow function has been reduced. The maximum values of the flow function for conventional nanofluid are greater than for hybrid nanofluid. The increment of the Nusselt number with increasing the volume fraction of nanoparticles in conventional nanofluid is more sensible comparing to hybrid nanofluid. Also with increasing the volume fraction of nanoparticles, the friction and thermal entropy generation is more sensible in conventional nanofluid comparing to hybrid nanofluid.