Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
NUMERICAL INVESTIGATION OF THE NATURAL CONVECTION PROCESS OF BINGHAM FLUID IN CLOSED CAVITY FILLED WITH HETEROGENEOUS MEDIA AND DIFFERENTLY HEATED SIDE WALLS
Submission Author:
Paulo Rutemberg Madeira Santos , PR
Co-Authors:
Paulo Rutemberg Madeira Santos, Alan Lugarini de Souza, Admilson Franco
Presenter: Paulo Rutemberg Madeira Santos
doi://10.26678/ABCM.COBEM2019.COB2019-1804
Abstract
Abstract: In the current study, the natural convection process of a yield stress fluid, which obeys the Bingham model in closed cavities filled with heterogeneous porous medium is investigated numerically. The problem is considered as laminar, two-dimensional and steady state regime with differentially heated vertical walls and adiabatic horizontal walls. In order to investigate the effects of significant parameters ( Ra, Bi ) that describe the flow field and heat transfer behavior . The Prandtl number is fixed as Pr=500 , the number of conductive blocks within the cavity is equal to N=64, the porosity is fixed to 0.64 ( fluid volume fraction ), evaluating the Rayleigh number in the range of 104 to 107 and Bingham number values in the range 0 to 1. As the Rayleigh number increases, the mean Nusselt number increases significantly for both Newtonian fluid and Bingham model. However, for the same Rayleigh number, the Nusselt numbers obtained for the Bingham fluids are lower than those obtained for the case with Newtonian fluids, due to the existing of yield stress that leads to a weakening of the convective transport. For high Bingham numbers the Nusselt number decreases, reaching a value of 1.872, where the heat transfer occurs mainly by conduction. Finally, it is stated that the conduction-dominated regime occurs at high values of and low values of Ra.
Keywords
Natural Convection, Enclosure, heterogeneous media, Bingham fluid, Computational fluid dynamics (CFD)
