Transient natural convection in a square enclosure with horizontal walls submitted to periodic temperatures

Journal Article · Fri Nov 26 04:00:00 EST 1999 · Numerical Heat Transfer. Part A, Applications

DOI:https://doi.org/10.1080/104077899274543· OSTI ID:20005612

Abourida, B; Hasnaoui, M; Douamna, S

Natural convection in enclosures is of considerable interest in several practical problems. Applications range from thermal design of buildings to solar collectors, electronic and computer equipment, etc. Here, natural convection in a square cavity with its horizontal walls submitted to different heating models has been investigated by a finite difference procedure. The hot temperature of the bottom surface varies sinusoidally with time, while that of the opposite surface (cold temperature) is maintained constant or varied sinusoidally. The vertical walls are considered adiabatic. Parameters of the problem are the amplitude of the variable temperature(s) (0 {le} a {le} 0.5), its (their) period (0.001 {le} {tau} {le} 1), the dephasing between hot and cold temperatures ({Phi} = 0 and {pi}), the Rayleigh number (5 x 10{sup 5} {le} Ra {le} 10{sup 6}) and the Prandtl number (Pr = 0.72). The effect of these parameters on heat transfer can be enhanced or reduced, with respect to the case of constant temperatures, by proper choice of the variable heating mode, the parameters related to the periodic temperature(s), and the Rayleigh number. By varying the two imposed temperatures, fundamental differences have been observed comparatively with the case of variable hot temperature and that of constant thermal boundary conditions.

• Research Organization: LMFE, Marrakesh (MA)
• OSTI ID: 20005612
• Journal Information: Numerical Heat Transfer. Part A, Applications, Journal Name: Numerical Heat Transfer. Part A, Applications Journal Issue: 7 Vol. 36; ISSN 1040-7782; ISSN NHAAES
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
ADIABATIC PROCESSES
BOUNDARY CONDITIONS
CAVITIES
FINITE DIFFERENCE METHOD
HEATING
NATURAL CONVECTION
TIME DEPENDENCE
WALLS