Impact of Thermal Source-Sink Arrangements on Buoyant Convection in a Nanofluid-Filled Annular Enclosure

Abstract

This investigation is devoted to analyze the buoyancy-driven flow behavior and associated thermal dissipation rate in a nanofluid-filled annular region with five different single source-sink and three different dual source-sink arrangements along the vertical surfaces. The remaining region on the vertical boundaries and horizontal surfaces are kept adiabatic. Numerical simulations have been performed by employing the finite difference method. To analyze the impacts of different nanofluids, nanoparticle volume fraction, Rayleigh number, size, and arrangement of sources and sinks, the results are graphically represented through streamline and isotherm contours, thermal profiles, average Nusselt number, and cup-mixing temperature. The results showed that identifying an optimum location and length of source-sink with a proper selection of other control parameters can lead to enhanced thermal transport and thermal mixing in the enclosure. In particular, middle-middle thermally active location and placing source-sink separately on the vertical walls lead to the production of maximum heat transport compared to other single and dual source-sink arrangements, respectively. Also, among the two nanofluids considered in the current investigation, larger enhancement in thermal transport has been achieved for Cu-water nanofluid. The calculated enhancement ratio of the heat dissipation rate enhances with an increment in nanoparticle concentration.