Computer Simulation of Natural Convection in a Square Cavity containing a Hot Body

Vitor José das Neves Rodrigues¹; Jian Su¹

¹ UFRJ

doi:10.20906/CPS/COB-2015-2642

Resumo

Natural convection in an enclosure is relevant to many industrial and environmental applications such as heat exchangers, nuclear and chemical reactors, cooling of electronic equipment, and stratified atmospheric boundary layers. A two-dimensional study for natural convection in an enclosure with a bottom wall at constant high temperature,a top wall at constant low temperature and a hot body inside the enclousure will be simulated numerically by using a tool of computational fluid dynamics (CFD), ANSYS CFX 15.0. The objective of the work is to study the influence of the geometry of the body, position of the body in the enclosure, fluid properties and mainly the temperature difference between the walls, in terms of of Prandtl and Rayleigh numbers. Steady-laminar, transient laminar and turbulent flow will be identified. Spectral analysis of instantaneous velocities and temperature by using FFT was performed for identify periodic or chaotic transient-laminar regimes. Critical Rayleigh numbers at which the onset of transient laminar regime was determined.

Palavras-chave: Natural Convection; Computational Fluid Dynamics