scholarly journals Resolving the stratification discrepancy of turbulent natural convection in differentially heated air-filled cavities. Part III: A full convection–conduction–surface radiation coupling

2013 ◽  
Vol 42 ◽  
pp. 33-48 ◽  
Author(s):  
Shihe Xin ◽  
Jacques Salat ◽  
Patrice Joubert ◽  
Anne Sergent ◽  
François Penot ◽  
...  
Keyword(s):  
Natural Convection ◽  
Surface Radiation ◽  
Turbulent Natural Convection ◽  
Heated Air

Effect of Surface Emissivity on Conjugate Turbulent Natural Convection in an Air-Filled Cavity with a Heat Source

2016 ◽  
Vol 685 ◽  
pp. 315-319 ◽  
Author(s):  
Igor V. Miroshnichenko ◽  
Mikhail A. Sheremet
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Surface Radiation ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Heat Conducting ◽  
Surface Emissivity ◽  
Turbulent Natural Convection ◽  
Effect Of Surface

The interaction of conjugate turbulent natural convection and surface thermal radiation in an air-filled square enclosure having heat-conducting solid walls of finite thickness and a heat source has been numerically studied. The primary focus was on the influence of surface emissivity on complex heat transfer. The mathematical model has been formulated in dimensionless variables such as stream function, vorticity and temperature using k-ε turbulent model. The effect of surface emissivity on the average total Nusselt number has been defined. The distributions of streamlines and temperature fields, describing characteristics of the analyzed fluid flow and heat transfer have been obtained. The results clearly show an essential effect of surface radiation on unsteady turbulent heat transfer.

Interaction Effects Between Surface Radiation and Turbulent Natural Convection in Square and Rectangular Enclosures

2001 ◽  
Vol 123 (6) ◽  
pp. 1062-1070 ◽  
Author(s):  
K. Velusamy ◽  
T. Sundararajan ◽  
K. N. Seetharamu
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Interaction Effects ◽  
Surface Radiation ◽  
Turbulent Natural Convection ◽  
Growth Regime ◽  
Wide Range ◽  
Different Temperatures ◽  
Vertical Walls

The interaction effects of surface radiation with turbulent natural convection of a transparent medium in rectangular enclosures have been numerically analyzed, covering a wide range of Rayleigh number from 109 to 1012 and aspect ratio from 1 to 200. The vertical walls of the enclosure are isothermal and maintained at different temperatures. The adiabatic top and bottom walls of the enclosure have been modelled for the limiting cases of negligible or perfect conduction along their lengths. The interaction with surface radiation results in larger velocity magnitudes and turbulence levels in the vertical as well as horizontal boundary layers, leading to an increase in the convective heat transfer by ∼25 percent. Due to the asymmetrical coupling of radiation, the augmentation of convective Nusselt number of the cold wall is larger than that of the hot wall. In tall enclosures, the convective Nusselt number exhibits three distinct regimes with respect to aspect ratio, viz. the slow growth regime, the accelerated growth regime and the invariant (or saturated) regime. The augmentation of convective Nusselt number for perfectly conducting horizontal walls is found to be of similar nature to that in the case with radiation interaction.

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