A new packed‐sphere model for geological materials thermal conductivity prediction at moderate porosity range for geothermal utilization

2019 ◽  
Vol 44 (12) ◽  
pp. 9479-9493
Author(s):  
G. S. Jia ◽  
Z. D. Ma ◽  
Y. Cao ◽  
X. Z. Meng ◽  
L. Y. Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Sphere Model ◽  
Geological Materials ◽  
Packed Sphere ◽  
Porosity Range

Radiative Transfer With Dependent Scattering by Particles: Part 1—Theoretical Investigation

1986 ◽  
Vol 108 (3) ◽  
pp. 608-613 ◽  
Author(s):  
J. D. Cartigny ◽  
Y. Yamada ◽  
C. L. Tien
Keyword(s):  
Radiative Transfer ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Spherical Particles ◽  
Sphere Model ◽  
Radiation Scattering ◽  
Particle Volume ◽  
Scattering Approximation ◽  
Regime Map ◽  
Packed Sphere

Dependent radiation scattering for which the independent scattering theory fails to predict the scattering properties is important in analyzing radiative transfer in packed and fluidized beds. In this paper the dependent scattering properties have been derived assuming the Rayleigh–Debye scattering approximation for two cases: two identical spheres and a cloud of spherical particles. The two-sphere calculated results compare well with the exact solutions in the literature, giving confidence in the present analytical approach. The gas model and packed-sphere model have been employed to calculate dependent scattering properties for a cloud of particles of small and large particle volume fraction, respectively. The calculated dependent scattering efficiencies for a cloud of particles are smaller than the independent scattering efficiencies and decrease with increasing particle volume fraction. A regime map for independent and dependent scattering has been constructed and compared with existing empirical criteria.

Thermal conductivity of aluminum foam based on 3‐D stochastic sphere model

Heat Transfer ◽  
2019 ◽  
Vol 49 (2) ◽  
pp. 823-837
Author(s):  
Minghan Sun ◽  
Meichen Fan ◽  
Lingxiao Li ◽  
Zhiqiang Xu ◽  
Tingsong Yang
Keyword(s):  
Thermal Conductivity ◽  
Aluminum Foam ◽  
Sphere Model

scholarly journals On the strength of packed spheres

1965 ◽  
Vol 5 (4) ◽  
pp. 443-452 ◽  
Author(s):  
A. K. Parkin
Keyword(s):  
Recent Trend ◽  
Sphere Model ◽  
Packed Sphere

The mechanics of a system of packed spheres has relevance to several physical disciplines. A particular case has been a recent trend among engineers to use a close-packed sphere model to aid research into the strength of cohesionless granular masses, such as sand.

A rough hard-sphere model for the thermal conductivity of molten salts

1992 ◽  
Vol 13 (5) ◽  
pp. 855-871 ◽  
Author(s):  
R. M. DiGuilio ◽  
A. S. Teja
Keyword(s):  
Thermal Conductivity ◽  
Hard Sphere ◽  
Molten Salts ◽  
Hard Sphere Model ◽  
Sphere Model

Contact Resistance Measurement and Its Effect on the Thermal Conductivity of Packed Sphere Systems

2004 ◽  
Vol 126 (6) ◽  
pp. 886-895 ◽  
Author(s):  
W. W. M. Siu ◽  
S. H.-K. Lee
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Effective Thermal Conductivity ◽  
Transient Behavior ◽  
Contact Radius ◽  
Transient Temperature ◽  
Interfacial Resistance ◽  
Conduction Model ◽  
Scale Modeling ◽  
Packed Sphere

There has been a growing interest in porous systems with a smaller length-scale modeling requirement on the order of each particle, where the existing tools tend to be inadequate. To address this, a Discrete Conduction Model was recently proposed to allow for the transient temperature calculation of 3D random packed-sphere systems for various microstructures. Since many of the motivating applications involve contacting spheres and since there has been a limited number of contact-resistance studies on spheres undergoing elastic deformation, the objective of this study is to obtain measurements of the contact resistances between metallic spheres in elastic contact, as well as to quantify their influence on the effective thermal conductivity. To accomplish this, an experiment was constructed utilizing air and interfacial resistance to replace the functions of the guard heater and vacuum chamber, and in so doing, enabled transient observations. The overall uncertainty was estimated to be ±6%, and the results were benchmarked against available data. A correlation was obtained relating the contact resistance with the contact radius, and results showed the contact resistance to have minimal transient behavior. The results also showed that the neglect of contact resistance could incur an error in the effective thermal conductivity calculation as large as 800%, and a guideline was presented under which the effect of the contact resistance may be ignored. A correlation accounting for the effect of contact resistance on the effective thermal conductivity was also presented.

Jellium sphere model in overlayer-substrate systems

1993 ◽  
Vol 3 (4) ◽  
pp. 1053-1058 ◽  
Author(s):  
Chen Lu-Jun ◽  
Wang Ning ◽  
Luo Enze
Keyword(s):  
Sphere Model
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