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Transient Flow of Air through Rectangular Vents in a Horizontal Partition
Transient laminar flow of air through rectangular vents in a horizontal partition between two large chambers was investigated. For vent aspect ratios of 1, 0.5, and 2, three flow regimes were identified as the Rayleigh number (Ra) was varied from 1 × 103 to 5 × 104 based on flow parameters in the vent and the corresponding modes of heat transfer through it. The critical control parameter was found to be the Rayleigh number, which determined the flow regimes of conduction, counter current, and oscillatory flow regimes. As the effective driving potential decreased with time, flow changed from one regime to the other such that higher Rayleigh number results showed all the three regimes over time. The circulation patterns within the vent for conduction regime (Ra < 1500) appeared to follow Chandrasekhar's (1961) well-known linear stability results. The flow exchange increases with partition thickness L/D = 0.5 and decreases for L/D = 2. At higher Ra, sudden bursts of upflow with a corresponding downflow were documented and compared with experimental observations in the literature. The time traces of velocity and temperature fields for this flow regime reveal interesting mechanisms, which have been explained.
Transient Flow of Air through Rectangular Vents in a Horizontal Partition
Transient laminar flow of air through rectangular vents in a horizontal partition between two large chambers was investigated. For vent aspect ratios of 1, 0.5, and 2, three flow regimes were identified as the Rayleigh number (Ra) was varied from 1 × 103 to 5 × 104 based on flow parameters in the vent and the corresponding modes of heat transfer through it. The critical control parameter was found to be the Rayleigh number, which determined the flow regimes of conduction, counter current, and oscillatory flow regimes. As the effective driving potential decreased with time, flow changed from one regime to the other such that higher Rayleigh number results showed all the three regimes over time. The circulation patterns within the vent for conduction regime (Ra < 1500) appeared to follow Chandrasekhar's (1961) well-known linear stability results. The flow exchange increases with partition thickness L/D = 0.5 and decreases for L/D = 2. At higher Ra, sudden bursts of upflow with a corresponding downflow were documented and compared with experimental observations in the literature. The time traces of velocity and temperature fields for this flow regime reveal interesting mechanisms, which have been explained.
Transient Flow of Air through Rectangular Vents in a Horizontal Partition
Sleiti, Ahmad K. (author)
HVAC&R Research ; 15 ; 1145-1163
2009-11-01
19 pages
Article (Journal)
Electronic Resource
Unknown
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