A. Rostamzadeh - School of Mechanical Engineering, Shiraz University, Shiraz, Iran Molasadra Str., Shiraz, ۷۱۹۳۶-۱۶۵۴۸, Iran.
E. Goshatsbi Rad - School of Mechanical Engineering, Shiraz University, Shiraz, Iran Molasadra Str., Shiraz, ۷۱۹۳۶-۱۶۵۴۸, Iran.
K. Jafarpur - School of Mechanical Engineering, Shiraz University, Shiraz, Iran Molasadra Str., Shiraz, ۷۱۹۳۶-۱۶۵۴۸, Iran.

In the present study, Lattice Boltzmann method is employed to investigate a two dimensional mixed convection heat transfer of Al۲O۳-water nanofluid in a horizontal annulus between a cold outer cylinder and the hot, rotating inner cylinder. To do so, the double lattice Boltzmann equation is utilized for the base fluid and the nanoparticles to describe the dynamic as well as the thermal behavior of nanofluid. Moreover, different forces such as Brownian, drag and gravity acting on the nanoparticles are taken into consideration. Calculations have been performed for Rayleigh number ranging from ۱۰۳ to ۲×۱۰۴, Reynolds number from ۵ to ۱۲۰, vertical and horizontal eccentricity from -۰.۷۵ to ۰.۷۵ with volume fraction of nanoparticles from ۰ to ۰.۱. The current computational results reveal that by adding nanoparticles, the mean Nusselt number for Ra ۱۰۴, it decreases. Also, with Re>۸۰, the mean Nusselt number increases with increasing Reynolds number; although for low Reynolds number this rising trend is not observed. Besides, when the inner cylinder moves vertically upward from the center, the addition of nanoparticles increases Nusselt number relative to the base fluid.

Multicomponent lattice Boltzmann method, Nanofluid, Eccentric annulus, Heat transfer, Nanoparticles