NUMERICAL SIMULATIONS OF NATURAL CONVECTION IN AN OPEN CAVITY WITH THE PRESENCE OF A SHROUDING WALL

Vanessa Glück Nardi¹; Admilson Teixeira Franco¹

¹ Federal University of Technology - Paraná

doi:10.20906/CPS/COB-2015-1849

Resumo

A study regarding natural convection is conducted for a square open cavity with the presence of a shrouding wall placed across the cavity opening, representing a short vertical channel. The cavity vertical wall is isothermal and the horizontal walls are kept adiabatic. Laminar and two-dimensional flow are assumed for Rayleigh number ranging from 103 to 107. Two boundary conditions are considered for the shrouding wall, namely adiabatic and isothermal, and the distance between the shrouding wall and the cavity opening varies between 0.1 and 0.5 times the cavity height. The fluid properties are assumed constant except for the buoyancy term in which is used the Oberbeck-Boussinesq approximation. The influence of Rayleigh number and the shrouding wall on the streamlines, isotherms, average Nusselt number and the velocity profiles at the top and bottom of channel are analyzed. The problem is numerically solved via the Finite Volume method. Given the difficulty in determining the boundary conditions at top (exit) and bottom (entrance) of the channel, extended domains are built in those regions. Numerical correlations are proposed for the average Nusselt number as a function of the Rayleigh number, the shrouding wall boundary condition and the distance between shrouding and the cavity opening.

Palavras-chave: natural convection; open cavity; shrouding wall