scholarly journals Full‐Field Modeling of Heat Transfer in Asteroid Regolith: Radiative Thermal Conductivity of Polydisperse Particulates

2020 ◽  
Vol 125 (2) ◽  
Author(s):  
Andrew J. Ryan ◽  
Daniel Pino Muñoz ◽  
Marc Bernacki ◽  
Marco Delbo
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Full Field ◽  
Field Modeling ◽  
Radiative Thermal Conductivity

scholarly journals Determination of Radiative Thermal Conductivity in Needlepunched Nonwovens

2008 ◽  
Vol 3 (4) ◽  
pp. 155892500800300 ◽  
Author(s):  
Rahul Vallabh ◽  
Pamela Banks-Lee ◽  
Massoud Mohammadi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Extinction Coefficient ◽  
Dominant Mode ◽  
Hot Plate ◽  
Guarded Hot Plate ◽  
Ftir Spectrometer ◽  
Radiative Thermal Conductivity

Radiation heat transfer is found to be the dominant mode of heat transfer at temperatures higher than 400–500K [11]. Convection heat transfer being negligible in nonwovens, effective thermal conductivity is given by the sum of its conduction and radiation components. In this research two methods were identified to determine radiative thermal conductivity of needlepunched samples made from Nomex fibers. The first method involved the determination of radiative thermal conductivity using effective (total) thermal conductivity determined using a Guarded Hot Plate (GHP) instrument. In the second method radiative thermal conductivity was estimated using the extinction coefficient of samples. The extinction coefficient was determined by using direct transmission measurements made using a Fourier Transform InfraRed (FTIR) spectrometer. Results confirmed that radiation was the dominant mode of heat transfer at temperatures higher than 535 K. The conduction component of effective thermal conductivity did not change much in the range of densities tested. Empirical models for predicting the temperature difference across thickness of the fabric and the radiative thermal conductivity with R-square values of 0.94 and 0.88 respectively showed that fabric density, fabric thickness, fiber fineness, fiber length, mean pore size and applied temperature were found to have significant effect on the effective thermal conductivity and its radiation component. Though a high correlation between the results of Method 1 (Guarded Hot Plate) and Method 2 (FTIR) was not seen, the absorbance measurements made using the FTIR spectrometer were found to have significant effect on the radiative thermal conductivity.

ALCOA QC-10

Alloy Digest ◽  
2009 ◽  
Vol 58 (7) ◽  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Aluminum Alloys ◽  
Physical Properties ◽  
Tensile Properties ◽  
Mold Material ◽  
Cast Products

Abstract Aluminum has long been accepted as a mold material. This alloy has a combination of faster machining, highest heat transfer, lighter weight, higher strength in thick sections, and greater thermal conductivity than other aluminum alloys. This datasheet provides information on physical properties, hardness, elasticity, and tensile properties. It also includes information on forming and machining. Filing Code: AL-423. Producer or source: Alcoa Forged and Cast Products.

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