Natural Convection Flow and Heat Transfer in Square Enclosure Asymetrically Heated from Below: A Lattice Boltzmann Comprehensive Study

• Published in: Computer modeling in engineering & sciences Vol. 88; no. 3; pp. 211 - 227
• Main Authors: Naffouti, Taoufik, Djebali, Ridha
• Format: Journal Article
• Language: English
• Published: Henderson Tech Science Press 2012
• Subjects: Boundary conditions; Ceilings; Computational fluid dynamics; Computer simulation; Convection; Enclosure; Enclosures; Fluid flow; Free convection; Grashof number; Heat transfer; Lattices; Mathematical analysis; Mathematical models; Prandtl number; Thermal analysis; Thermal energy; Viscosity; Walls
• ISSN: 1526-1492; 1526-1506
• DOI: 10.3970/cmes.2012.088.211

This paper reports numerical results of natural convection flow evolving inside confined medium defined by two-dimensional square enclosure containing isothermal hot source placed asymmetrically at bottom wall. The sides-walls are isothermally cooled at a constant temperature; however the ceiling and the rest of bottom wall are insulated. The lattice Boltzmann method is used to solve the dimensionless governing equations with the associated boundary conditions. The flow is monitored by the Grashof number and the Prandtl number taken here 0.71. Numerical simulations are performed to study the effects of Grashof number ranging from 104 to 106, hot source length from 0.1 to 0.4 and its position ranging from 0.15 and 0.45, on flow and heat transfer behaviours. It was found that the developed lattice Boltzmann thermal model give credible results by comparison with former findings. Additionally, it was found that the Grashof number increase as well as the source length results in enhancing the convective currents and then heat transfer rate quantified by the Nusselt number along the hot source. Besides, the variation of the hot source position affects the dynamic and thermal structures and increases slightly the heat transfer to a rate of 5%.