Natural convection in an air layer enclosed within rectangular cavities

Yin, Shi; Wung, T.Y.; Chen, Kung

doi:10.1016/0017-9310(78)90123-0

Cited by 113 publications

(61 citation statements)

References 8 publications

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“…According to previous investigations on natural convection and heat transfer in enclosed air cavities (Yin et al, 1978), the flow regime can be classified in conduction, transition and boundary layer regime, depending on the Rayleigh number and the aspect ratio of the air cavity.…”

Section: Temperature Distribution In the Air Cavitymentioning

confidence: 99%

Influence of natural ventilation due to buoyancy and heat transfer in the energy efficiency of a double skin facade building

Sánchez

Rolando

Sant

et al. 2016

Energy for Sustainable Development

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Available online xxxxIn recent years, the interest in double skin facades has increased because of esthetic reasons and for its use as passive system to save energy. Some authors have investigated their behavior related to thermal performance and energy efficiency compared to single skin facades but only considering the air cavity. The aim of this work is to identify a more efficient double glazed facade configuration that improves energy efficiency and indoor comfort conditions in buildings studying natural ventilation due to buoyancy-driven flow and heat transfer including solar radiation compared to a single skin facade. A simplified model was simulated using a computational fluid dynamics software to investigate the effects due to different cavity widths in winter and summer conditions with opened and closed vents and considering solar radiation or not. The main results obtained were that in winter closed vents is always efficient and ventilating is never beneficial. In summer closed vents is efficient in the absence of solar radiation and in its presence opened vents is favorable. Results showed the optimum air cavity width, and it was concluded that these double skin facades reduce the heating and cooling demands of a building, being more efficient compared to single skin facades.

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Section: Temperature Distribution In the Air Cavitymentioning

confidence: 99%

Influence of natural ventilation due to buoyancy and heat transfer in the energy efficiency of a double skin facade building

Sánchez

Rolando

Sant

et al. 2016

Energy for Sustainable Development

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“…Several investigators present data for heat transfer across an air space in the range of interest [8][9][10][11]. Yin's [9] experiments covered the complete Grashof number and aspect ratio range of interest in this work.…”

Section: Natural Convection In the Airmentioning

confidence: 99%

“…Yin's [9] experiments covered the complete Grashof number and aspect ratio range of interest in this work. Yin took data over the Grashof number range of 1.5 × 10 3 to 7.0 × 10 6 and covered the aspect ratio range of 4.9 to 78.7.…”

Section: Natural Convection In the Airmentioning

confidence: 99%

Thermal Analysis of ZPPR High Pu Content Stored Fuel

Solbrig

Pope

Andrus

2014

International Journal of Nuclear Energy

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The Zero Power Physics Reactor (ZPPR) operated from April 18, 1969April 18, , until 1990. ZPPR operated at low power for testing nuclear reactor designs. This paper examines the temperature of Pu content ZPPR fuel while it is in storage. Heat is generated in the fuel due to Pu and Am decay and is a concern for possible cladding damage. Damage to the cladding could lead to fuel hydriding and oxidizing. A series of computer simulations were made to determine the range of temperatures potentially occuring in the ZPPR fuel. The maximum calculated fuel temperature is 292 ∘ C (558 ∘ F). Conservative assumptions in the model intentionally overestimate temperatures. The stored fuel temperatures are dependent on the distribution of fuel in the surrounding storage compartments, the heat generation rate of the fuel, and the orientation of fuel. Direct fuel temperatures could not be measured but storage bin doors, storage sleeve doors, and storage canister temperatures were measured. Comparison of these three temperatures to the calculations indicates that the temperatures calculated with conservative assumptions are, as expected, higher than the actual temperatures. The maximum calculated fuel temperature with the most conservative assumptions is significantly below the fuel failure criterion of 600 ∘ C (1,112 ∘ F).

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“…Overall, the objective of these studies is to determine the flow structure and the convective heat transfer in vertical cavities filled with air and of an aspect ratio = 4 to 80. Nusselt numbers calculated numerically by Manz (2003) were compared with those estimated by some widely used correlations (Yin et al 1978;ElSherbiny et al 1982;Wright 1996;Zhao et al 1997). While the results of Xàman et al (2005) have been exploited to develop, in laminar and turbulent regimes for each (20, 40, and 80), simple empirical expressions giving the average Nusselt number as a function of the Rayleigh number.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Turbulent Natural Convection by an Elliptic Relaxation Model in Tall Vertical Cavities with Linear Temperatures on Sidewalls

Moutaouakil

Zrikem

Abdelbaki

2017

JAFM

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Turbulent natural convection of air is studied, by the elliptic-relaxation model − , in a tall vertical cavity whose hot and cold walls are maintained at linear temperatures of slopes and , respectively. The average temperatures of the active walls are located at mid-height of the cavity. Four situations are analyzed, corresponding to = = (case I ), = − = (case II ), = 0 and = (case III ), = and = 0 (case IV). These boundary conditions may be more representative or used to control heat transfer for certain systems. The effects of the slope (−1 ≤ ≤ 1), the aspect ratio of the cavity (10 ≤ ≤ 80) and the average Rayleigh number (5 × 10 ≤ ≤ 10 ) on the streamlines, isotherms, contours of the turbulent kinetic energy, heatlines, local and average Nusselt numbers are investigated. It is shown that the local and average heat transfers of cases III and IV can be deducted from those of cases I and II. The obtained dynamic and thermal fields as well as local and average heat transfers of the studied cases are quite different of those of the classical case corresponding to = 0. A simplified procedure for calculating the average Nusselt number is also developed for each case.

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Natural convection in an air layer enclosed within rectangular cavities

Cited by 113 publications

References 8 publications

Influence of natural ventilation due to buoyancy and heat transfer in the energy efficiency of a double skin facade building

Influence of natural ventilation due to buoyancy and heat transfer in the energy efficiency of a double skin facade building

Thermal Analysis of ZPPR High Pu Content Stored Fuel

Analysis of Turbulent Natural Convection by an Elliptic Relaxation Model in Tall Vertical Cavities with Linear Temperatures on Sidewalls

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