RETRACTED: Numerical study on free convection in a U-shaped CuO/water nanofluidfilled cavity with different aspect ratios using double-MRT lattice Boltzmann

Abstract

Abstract The lattice Boltzmann simulation of natural convection fluid flow and heat transfer is performed. The double-MRT lattice Boltzmann method is employed. The D2Q5 and D2Q9 lattice models are used to simulate the temperature field and flow field, respectively. The configuration of the cavity is U-shaped, and the cavity is filled with CuO-water nanofluid. The KKL (Koo-Kleinstreuer-Li) model is utilized to estimate the thermal conductivity and dynamic viscosity; as well as, the nanoparticle shape effect on the thermo-physical properties of nanofluid is considered. The streamlines, temperature distribution, local entropy generation map, average Nusselt number, magnitude of total entropy generation and magnitude of Bejan number under influence of Rayleigh number (103 h / w = 1 , h / w = 1.5 , h / w = 2 and h / w = 2.5 ) are presented and discussed, comprehensively.