Numerical solution for laminar mixed convection in a horizontal annular duct: Temperature-dependent viscosity effect

Autor: C. Nouar
Rok vydání: 1999
Předmět:
Zdroj: International Journal for Numerical Methods in Fluids. 29:849-864
ISSN: 1097-0363
0271-2091
DOI: 10.1002/(sici)1097-0363(19990415)29:7<849::aid-fld820>3.0.co;2-f
Popis: The influence of free convection and variable viscosity on forced laminar flow of a Newtonian fluid in a horizontal annular duct is investigated. The inner and outer cylinders are subjected to a constant heat flux density. At the entrance of the annular duct, the flow is fully developed and the temperature profile is uniform. The Prandtl and Boussinesq hypothesis were adopted. The continuity equation and the three-dimensional parabolized form of the momentum and energy equations are solved numerically using finite differences. Near the entrance section, forced convection is the dominant mechanism. Further downstream, the fluid heats up and buoyancy becomes more important. The fluid near the walls is warmer, and therefore lighter than the fluid in the central part of the annular space; it therefore flows upward along the walls. A continuity requires a downflow of the heavier fluid between the two cylinders. This secondary flow modifies the structure of the dynamic and thermal fields
Databáze: OpenAIRE