Effects of cavity and heat source aspect ratios on natural convection of a nanofluid in a C-shaped cavity using Lattice Boltzmann method

Purpose The purpose of this paper is to consider natural convection of a nanofluid inside of a C-shaped cavity using Lattice Boltzmann method (LBM). Design/methodology/approach Effects of some geometry and flow parameters consisting of the aspect ratio of the cavity, aspect ratio of the heat source; Rayleigh number (Ra = 10 3 − 10 6 ) have been investigated. The validity of the method is checked by comparing the present results with ones from the previously published work. Findings The results demonstrate that for Ra = 10 3 , the aspect ratio of the heat source has more influence on the average Nusselt number in contrast to the case of Ra = 10 6 . Contrary to the fact that the average Nusselt number increases non-linearly more than twice because of the increase of the aspect ratio of the enclosure at Ra = 10 3 , the average Nusselt number has a linear relation with the aspect ratio for of Ra = 10 6 . Therefore, upon increasing the Rayleigh number, the efficiency of the aspect ratio of the cavity on the thermal convection, gradually diminishes. Originality/value The authors believe that all the results, both numerical and asymptotic, are original and have not been published elsewhere.