Effect of Surface Radiation on the Natural-Convection Stability in a Two-Dimensional Enclosure with Diffusely Emitting Boundary Walls

• Published in: Numerical heat transfer. Part A, Applications Vol. 51; no. 5; pp. 495 - 516
• Main Authors: Jaballah, S., Sammouda, H., Belghith, A.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 22.02.2007
• ISSN: 1040-7782; 1521-0634
• DOI: 10.1080/10407780600829605

A transient interaction of natural convection with thermal radiation of gray surfaces of a square cavity filled with air is investigated numerically. The effect of radiation on the flow field, temperature distribution, and onset of oscillatory instability of flow is predicted. A complete study of stability of some value of Rayleigh number is performed for emissivity ε varying from 0 to 1. The finite-element and the fractional step time methods are used to solve the two-dimensional time-dependent Navier-Stokes and energy equations. The results are reduced in terms of the time-series averages Nusselt number and velocity component near vertical walls and at the center of the cavity. The Grashof number is varied up to 5 × 10 7 to determine the new critical values of regime flow for different values of emissivity.