Analysis and Measurements of Interzonal Natural Convection Heat Transfer in Buildings

1986 ◽  
Vol 108 (3) ◽  
pp. 178-184 ◽  
Author(s):  
D. Hill ◽  
A. Kirkpatrick ◽  
P. Burns
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Rate ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Bernoulli Model ◽  
Convection Heat ◽  
Important Process ◽  
Temperature Distributions ◽  
Good Agreement

Natural convection heat transfer through doorways can be an important process by which thermal energy is transferred from one zone to another zone of a building. The topic of this paper is interzonal natural convection in a two zone and a three zone multilevel full scale building. Aperture velocity and temperature distributions are measured and the experimental interzonal mass flow rate and heat transfer are determined. A Bernoulli model is derived to predict the neutral heights, velocity profiles, and interzonal heat transfer. The measured and predicted interzonal flow rate and heat transfer are compared and found to be in good agreement.

Modeling the Natural Convection Heat Transfer and Dryout Heat Flux in a Porous Debris Bed

2008 ◽  
Vol 130 (10) ◽  
Author(s):  
R. Sinha ◽  
A. K. Nayak ◽  
B. R. Sehgal
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Severe Accident ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Wide Range ◽  
Particulate Debris ◽  
Limiting Condition ◽  
Good Agreement

An empirical model for natural convection heat transfer for film-boiling condition has been developed for volumetrically heated particulate debris beds when flooded with water at the top of the bed. The model has been derived from the quenching data generated in the POMECO facility located at KTH, Stockholm. A dryout model is also developed for countercurrent flooding limiting condition when the heat generating saturated debris bed is flooded with water from the top. The model is in good agreement with the experimental data over a wide range of particle size and porosity as compared to the existing models. The implication of the models with respect to quenching of porous debris bed formed during postulated severe accident condition is discussed.

Natural Convection Heat Transfer in a Vertical Square Duct With Radiation Effects

1999 ◽  
Author(s):  
Wei-Mon Yan ◽  
Kuan-Tzong Lee
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Rate ◽  
Radiation Effects ◽  
Volume Flow Rate ◽  
Convection Heat Transfer ◽  
Volume Flow ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Square Duct

Abstract The present work investigates numerically the natural convection heat transfer with radiation effects in an open vertical square duct. The integro-differential radiative transfer equation is solved by discrete ordinates method. The vorticity-velocity formulation is applied to solve for the coupled momentum and energy equations. The effects of five major parameters, Grashof number Gr, conduction-to-radiation parameter Nc, optical thickness τ, single scattering albedo ω and temperature ratio Tr, on the combined natural and radiation heat transfer are discussed in detail. The numerical results of the dimensionless induced volume flow rate and average Nusselt numbers show that the thermal radiation would enhance the heat transfer rate. Additionally, the variations of the induced volume flow rate and total Nusselt number are independent of radiative parameters under fully-developed flow limit.

Natural Convection Heat Transfer for a Concentric Tube Thermosiphon

1985 ◽  
Vol 107 (3) ◽  
pp. 583-588 ◽  
Author(s):  
J. L. Steimke
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Single Phase ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Flow Loop ◽  
Model Equations ◽  
Steady Laminar ◽  
Good Agreement

Natural convection heat transfer for a single-phase thermosiphon formed by two concentric tubes and a central rod filled with water is studied theoretically and experimentally. The two annuli between the tubes and the rod are joined at the top and bottom and form a flow loop. The middle tube is heated while the outer tube is cooled. In this one-dimensional model equations for continuity, momentum, and energy for steady laminar flow are written and solved numerically. There is reasonably good agreement between the analytically and experimentally determined temperatures and convective velocities in the thermosiphon.

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