scholarly journals Calculation of the thermal conductivity of low-density CH4–N2gas mixtures using an improved kinetic theory approach

2016 ◽  
Vol 144 (13) ◽  
pp. 134301 ◽  
Author(s):  
Robert Hellmann ◽  
Eckard Bich ◽  
Velisa Vesovic
Keyword(s):  
Thermal Conductivity ◽  
Kinetic Theory ◽  
Low Density ◽  
Theory Approach

scholarly journals Thermal conductivity of strained silicon: Molecular dynamics insight and kinetic theory approach

2019 ◽  
Vol 126 (5) ◽  
pp. 055109 ◽  
Author(s):  
Vasyl Kuryliuk ◽  
Oleksii Nepochatyi ◽  
Patrice Chantrenne ◽  
David Lacroix ◽  
Mykola Isaiev
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Kinetic Theory ◽  
Strained Silicon ◽  
Theory Approach

scholarly journals Thermophysical Properties of Multifunctional Syntactic Foams Containing Phase Change Microcapsules for Thermal Energy Storage

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1790
Author(s):  
Francesco Galvagnini ◽  
Andrea Dorigato ◽  
Luca Fambri ◽  
Giulia Fredi ◽  
Alessandro Pegoretti
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Epoxy Resin ◽  
Storage Modulus ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Neat Epoxy ◽  
Low Density ◽  
Syntactic Foams

Syntactic foams (SFs) combining an epoxy resin and hollow glass microspheres (HGM) feature a unique combination of low density, high mechanical properties, and low thermal conductivity which can be tuned according to specific applications. In this work, the versatility of epoxy/HGM SFs was further expanded by adding a microencapsulated phase change material (PCM) providing thermal energy storage (TES) ability at a phase change temperature of 43 °C. At this aim, fifteen epoxy (HGM/PCM) compositions with a total filler content (HGM + PCM) of up to 40 vol% were prepared and characterized. The experimental results were fitted with statistical models, which resulted in ternary diagrams that visually represented the properties of the ternary systems and simplified trend identification. Dynamic rheological tests showed that the PCM increased the viscosity of the epoxy resin more than HGM due to the smaller average size (20 µm vs. 60 µm) and that the systems containing both HGM and PCM showed lower viscosity than those containing only one filler type, due to the higher packing efficiency of bimodal filler distributions. HGM strongly reduced the gravimetric density and the thermal insulation properties. In fact, the sample with 40 vol% of HGM showed a density of 0.735 g/cm3 (−35% than neat epoxy) and a thermal conductivity of 0.12 W/(m∙K) (−40% than neat epoxy). Moreover, the increase in the PCM content increased the specific phase change enthalpy, which was up to 68 J/g for the sample with 40 vol% of PCM, with a consequent improvement in the thermal management ability that was also evidenced by temperature profiling tests in transient heating and cooling regimes. Finally, dynamical mechanical thermal analysis (DMTA) showed that both fillers decreased the storage modulus but generally increased the storage modulus normalized by density (E′/ρ) up to 2440 MPa/(g/cm3) at 25 °C with 40 vol% of HGM (+48% than neat epoxy). These results confirmed that the main asset of these ternary multifunctional syntactic foams is their versatility, as the composition can be tuned to reach the property set that best matches the application requirements in terms of TES ability, thermal insulation, and low density.

Analysis of binary and ternary granular mixtures behavior using the kinetic theory approach

2005 ◽  
Vol 151 (1-3) ◽  
pp. 117-125 ◽  
Author(s):  
Hadjira Iddir ◽  
Hamid Arastoopour ◽  
Christine M. Hrenya
Keyword(s):  
Kinetic Theory ◽  
Theory Approach ◽  
Granular Mixtures

Boundary-value problems in the kinetic theory of gases. Part 2. Thermal creep

1971 ◽  
Vol 45 (4) ◽  
pp. 759-768 ◽  
Author(s):  
M. M. R. Williams
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Temperature Gradient ◽  
Kinetic Theory ◽  
Effective Thermal Conductivity ◽  
Half Space ◽  
Thermal Creep ◽  
Kinetic Theory Of Gases ◽  
Boundary Wall ◽  
Creep Velocity

The effect of a temperature gradient in a gas inclined at an angle to a boundary wall has been investigated. For an infinite half-space of gas it is found that, in addition to the conventional temperature slip problem, the component of the temperature gradient parallel to the wall induces a net mass flow known as thermal creep. We show that the temperature slip and thermal creep effects can be decoupled and treated quite separately.Expressions are obtained for the creep velocity and heat flux, both far from and at the boundary; it is noted that thermal creep tends to reduce the effective thermal conductivity of the medium.

Thermal Conductivity of Low Density Polyethylene Foams Part I: Comprehensive Study of Theoretical Models

2019 ◽  
Vol 28 (4) ◽  
pp. 745-754 ◽  
Author(s):  
Hasanzadeh Rezgar ◽  
Azdast Taher ◽  
Doniavi Ali ◽  
Eungkee Lee Richard
Keyword(s):  
Thermal Conductivity ◽  
Theoretical Models ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Comprehensive Study
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