Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

NUMERICAL COMPUTATION OF NATURAL CONVECTION IN A CUBICAL ENCLOSURE WITH VENTILATION FOR BOTH A LAMINAR AND A TWO-EQUATION TURBULENT MODEL

Get access (open in a dialog) DOI: 10.1615/IHTC8.3030
pages 1489-1494

Abstrakt

Three-dimensional numerical computation was carried out for natural convection with ventilation through slit openings in a cubic enclosure at Ra=107 and Pr=0.7. Computation was carried out for both a laminar model and a k−ε type two-equation model. The Nusselt number at Ra=106 computed with a laminar model without ventilation was 3% less than that with a k−ε model. However, at Ra=107, a turbulent model gave 13.7% higher value of the Nusselt number than a laminar model. This appears to indicate a development of flow toward a turbulent state at this higher Rayleigh number. For the system with ventilation, fluid flows into the regime through a slit and then goes to the side walls. After a steady state of the flow is accomplished, fresh air was introduced into the system through an inlet or two inlets stepwise. The concentration profile of fresh air after one space time of a plug flow revealed that fresh air was found to be much denser along both side walls rather than in the central regime. Since two-dimensional model can give the flow characteristics only at the central regime, this result suggests the importance of three-dimensional analysis for systems both with or without ventilation.