Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
COMPUTATIONAL STUDY OF TWO-DIMENSIONAL NATURAL CONVECTION IN A CONCENTRIC HORIZONTAL ANNULUS WITH A CONSTANT HEAT FLUX WALL
Submission Author:
Larissa Pinheiro , RJ
Co-Authors:
Su Jian, Arthur de Oliveira
Presenter: Larissa Pinheiro
doi://10.26678/ABCM.ENCIT2016.CIT2016-0576
Abstract
Natural convection in horizontal annulus is a fundamental heat transfer problem and can be found in a variety of engineering applications, such as heat exchangers, cooling of electronic components, and thermal insulation. Due to its importance, natural convection in horizontal annulus has been studied extensively in literature. Most of the published researches are devoted to the study of the flow and heat distribution under fixed wall temperature difference. However, systems with the inner cylinder with a prescribed heat flux also have practical interest, such as the heat flux from electrical wire causing the heating of an external cylinder due to Joule's effect. In the present work, we studied two-dimensional steady-state natural convection in a horizontal concentric annulus with the external surface at constant temperature and the inner surface at constant heat flux. The flow and heat transfer characteristics are governed by three dimensionless groups: Rayleigh number Ra, Prandtl number Pr, and the aspect ratio R, defined as the ratio of external and inner radii. Computational simulations were carried out by using the CFD package ANSYS CFX 15.0. The Prandtl number is taken as 0.7. Multiple steady state solutions were found with different number of vortexes for a given aspect ratio R and Rayleigh number RaH. Flow pattern transition occurs at a critical Rayleigh number (Rac). The influence of the aspect ratio on heat transfer rate is determined for 1.22 < R < 3.0.
Keywords
heat tranfer, Natural Convection, horizontal annulus, CFD, heat tranfer, Natural Convection, horizontal annulus, CFD, heat tranfer, Natural Convection, horizontal annulus, CFD, Natrural convection, CFD, Horizontal concentric annulus, Heat transfer, heat tranfer, Natural Convection, horizontal annulus, CFD, Natrural convection, Horizontal concentric annulus, Heat transfer, heat tranfer, Natural Convection, horizontal annulus, CFD, Natrural convection, Horizontal concentric annulus, Heat transfer
