Gas‐phase evolution and convective heat transfer in closed‐cell vapor transport of organic thin films in microgravity and unit gravity

1990 ◽  
Vol 8 (1) ◽  
pp. 49-60 ◽  
Author(s):  
M. K. Debe ◽  
R. J. Poirier ◽  
E. L. Cook ◽  
L. R. Miller ◽  
M. S. Spiering ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thin Films ◽  
Convective Heat Transfer ◽  
Gas Phase ◽  
Convective Heat ◽  
Organic Thin Films ◽  
Phase Evolution ◽  
Vapor Transport ◽  
Closed Cell

scholarly journals Numerical Study Using Microstructure Based Finite Element Modeling of the Onset of Convective Heat Transfer in Closed-Cell Polymeric Foam

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1769
Author(s):  
Jorge-Enrique Rivera-Salinas ◽  
Karla-Monzerratt Gregorio-Jáuregui ◽  
Heidi-Andrea Fonseca-Florido ◽  
Carlos-Alberto Ávila-Orta ◽  
Eduardo Ramírez-Vargas ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Finite Element ◽  
Natural Convection ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Numerical Study ◽  
Heat Transfer Mode ◽  
Transfer Mode ◽  
Closed Cell

The thermal performance of closed-cell foams as an insulation device depends on the thermal conductivity. In these systems, the heat transfer mode associated with the convective contribution is generally ignored, and studies are based on the thermo-physical properties that emerge from the conductive contribution, while others include a term for radiative transport. The criterion found in the literature for disregarding convective heat flux is the cell diameter; however, the cell size for which convection is effectively suppressed has not been clearly disclosed, and it is variously quoted in the range 3–10 mm. In practice, changes in thermal conductivity are also attributed to the convection heat transfer mode; hence, natural convection in porous materials is worthy of research. This work extends the field of study of conjugate heat transfer (convection and conduction) in cellular materials using microstructure-based finite element analysis. For air-based insulating materials, the criteria to consider natural convection (Ra=103) is met by cavities with sizes of 9.06 mm; however, convection is developed into several cavities despite their sizes being lower than 9.06 mm, hence, the average pore size that can effectively suppress the convective heat transfer is 6.0 mm. The amount of heat transported by convection is about 20% of the heat transported by conduction within the foam in a Ra=103, which, in turn, produces an increasing average of the conductivity of about 4.5%, with respect to a constant value.

INTERFACIAL CONVECTIVE HEAT TRANSFER FOR RANDOMLY GENERATED POROUS MEDIA

2018 ◽  
Vol 49 (1) ◽  
pp. 77-90
Author(s):  
Eren Ucar ◽  
Moghtada Mobedi ◽  
Azita Ahmadi
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Convective Heat Transfer ◽  
Convective Heat
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