The comparative investigation of three approaches to modeling the natural convection heat transfer: A case studyon conical cavity filled with Al2O3 nanoparticles

Abstract

The cornerstone of a new method to modeling nanofluids is particle movement. There are three primary forms of nanofluid simulation. The single-phase modeling with nanofluid properties (SPU), the multiphase fluid with discrete particle (MDP) and the discrete element method with particle (DEMP). In this study, by comparing three approaches to modeling the natural convection heat transfer in nanofluid, this method's (discrete element method with particle) ability was examined to predict properties and processes, such as heat transfer and friction factor. With a high range of Rayleigh numbers (0 ≤ Ra ≤ 100, 000), this method tries to model the natural convection process in a conical cavity filled with Al2O3 nanofluid and nanoparticles. For modeling the MDP and thermophoresis effect (DEMP), a unique code with a novel grid generation algorithm was developed. The results demonstrated that the initial conditions determined the accuracy of the three methods for modeling the final parameters of natural convection within the conical cavity, the accuracy of the used equations, the procedure through which the boundary conditions were applied and the Rayleigh number. Accordingly, the DEMP and MDP methods were recommended for low Rayleigh numbers and those beyond 5500, respectively.