Laminar natural convection in a vertical isothermal channel with symmetric surface-mounted rectangular ribs

• Published in: The International journal of heat and fluid flow Vol. 23; no. 4; pp. 519 - 529
• Main Authors: Desrayaud, Gilles, Fichera, Alberto
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.08.2002; Elsevier Science
• Subjects: Control volume method; Convection and heat transfer; Exact sciences and technology; Flows in ducts, channels, nozzles, and conduits; Fluid dynamics; Fundamental areas of phenomenology (including applications); Isothermal channel; Natural convection; Physics; Rectangular rib; Turbulent flows, convection, and heat transfer; Rectangular rib; Natural convection; Isothermal channel; Control volume method; Isothermal condition; Streamlines; Nusselt number; Mass flow rate; Pipe flow; Laminar flow; Vertical pipe; Digital simulation; Rib; Aspect ratio
• ISSN: 0142-727X; 1879-2278
• DOI: 10.1016/S0142-727X(02)00136-4

In this paper, a numerical investigation of laminar natural convective flows in a vertical isothermal channel with two rectangular ribs, symmetrically located on each wall, is carried out. The governing elliptic equations are solved in a two-dimensional domain using a control volume method and the SIMPLER algorithm for the velocity–pressure coupling is employed. Special emphasis is given in the systematic analysis to detail the effects of the location of the isothermal ribs on the flow structure and isotherms pattern. The profiles of the local Nusselt number are presented for three different locations of the obstructions, near the inlet, at the center and near the outlet of the channel. The influence of the rib conductivity is also considered, the ribs being either perfectly conducting or adiabatic. The variations in the mean Nusselt number and inlet flow rate versus the channel Rayleigh number are investigated. Finally, for centered ribs extra computations are performed for various sizes (width and length) of the ribs and for two aspect ratios to demonstrated the significant effects on the flow and heat transfer characteristics.