Effective Thermal Conductvity of Three-Phase Soils

2012 ◽  
Author(s):  
Fabio Gori ◽  
Sandra Corasaniti
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Heat Fluxes ◽  
Water Volume ◽  
Two Phase ◽  
Empirical Constant ◽  
Three Phase ◽  
Theoretical Predictions ◽  
Porosity Ratio ◽  
Good Agreement

The aim of the present paper is to determine the effective thermal conductivity of three-phase soils, made of a quasi-spherical solid grain, and surrounded by two phase, which can be water and air or water and ice. The effective thermal conductivity is obtained theoretically by integrating the conduction equation under the thermal distribution of parallel heat fluxes in steady-state. The effective thermal conductivity is evaluated at a given degree of porosity (ratio between the void volume and the total one) and different degrees of saturation (ratio between the water volume and the void one) from dryness up to saturation. Comparisons between experimental data and theoretical predictions confirm that the present model can predict the effective thermal conductivity with a fairly good agreement without using any empirical constant.

scholarly journals Numerical and Experimental Evaluation of Thermal Conductivity: An Application to Al-Sn Alloys

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 650
Author(s):  
Ziwei Li ◽  
Chiara Confalonieri ◽  
Elisabetta Gariboldi
Keyword(s):  
Thermal Conductivity ◽  
Composite Materials ◽  
Effective Thermal Conductivity ◽  
Laser Flash ◽  
Miscibility Gap ◽  
Two Phase ◽  
Lattice Monte Carlo ◽  
Three Phase ◽  
Laser Flash Analysis ◽  
Good Agreement

Evaluation of thermal conductivity of composite materials is extremely important to control material performance and stability in thermal applications as well as to study transport phenomena. In this paper, numerical simulation of effective thermal conductivity of Al-Sn miscibility gap alloys is validated with experimental results. Lattice Monte-Carlo (LMC) method is applied to two-phase and three-phase materials, allowing to estimate effective thermal conductivity from micrographs and individual phase properties. Numerical results are compared with literature data for cast Al-Sn alloys for the two-phase model and with a specifically produced powder metallurgy Al-10vol%Sn, tested using laser flash analysis, for a three-phase simulation. A good agreement between numerical and experimental data was observed. Moreover, LMC simulations confirmed the effect of phase morphology as well as actual phase composition on thermal conductivity of composite materials.

Prediction of effective thermal conductivity of two-phase porous media by nomogram

1974 ◽  
Vol 24 (8) ◽  
pp. 437-445 ◽  
Author(s):  
P. B. Lal Chaurasia ◽  
D. R. Chaudhary ◽  
R. C. Bhandari
Keyword(s):  
Thermal Conductivity ◽  
Porous Media ◽  
Effective Thermal Conductivity ◽  
Two Phase

scholarly journals A Generalized Approach for Evaluating the Mechanical Properties of Polymer Nanocomposites Reinforced with Spherical Fillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 830
Author(s):  
Julio Cesar Martinez-Garcia ◽  
Alexandre Serraïma-Ferrer ◽  
Aitor Lopeandía-Fernández ◽  
Marco Lattuada ◽  
Janak Sapkota ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymeric Nanocomposites ◽  
Mechanical Reinforcement ◽  
Future Studies ◽  
Three Phase ◽  
Theoretical Predictions ◽  
Filler Network ◽  
New Research ◽  
Good Agreement ◽  
Research Avenue

In this work, the effective mechanical reinforcement of polymeric nanocomposites containing spherical particle fillers is predicted based on a generalized analytical three-phase-series-parallel model, considering the concepts of percolation and the interfacial glassy region. While the concept of percolation is solely taken as a contribution of the filler-network, we herein show that the glassy interphase between filler and matrix, which is often in the nanometers range, is also to be considered while interpreting enhanced mechanical properties of particulate filled polymeric nanocomposites. To demonstrate the relevance of the proposed generalized equation, we have fitted several experimental results which show a good agreement with theoretical predictions. Thus, the approach presented here can be valuable to elucidate new possible conceptual routes for the creation of new materials with fundamental technological applications and can open a new research avenue for future studies.

Effective thermal conductivity of two-dimensional anisotropic two-phase media

2013 ◽  
Vol 63 ◽  
pp. 41-50 ◽  
Author(s):  
Amir Akbari ◽  
Mohsen Akbari ◽  
Reghan J. Hill
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Two Dimensional ◽  
Two Phase

Brownian-Motion-Based Convective-Conductive Model for the Effective Thermal Conductivity of Nanofluids

2005 ◽  
Vol 128 (6) ◽  
pp. 588-595 ◽  
Author(s):  
Ravi Prasher ◽  
Prajesh Bhattacharya ◽  
Patrick E. Phelan
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Particle Sizes ◽  
Brownian Movement ◽  
Liquid Temperature ◽  
Interfacial Resistance ◽  
Conduction Model ◽  
Order Of Magnitude ◽  
Base Liquid ◽  
Good Agreement

Here we show through an order-of-magnitude analysis that the enhancement in the effective thermal conductivity of nanofluids is due mainly to the localized convection caused by the Brownian movement of the nanoparticles. We also introduce a convective-conductive model which accurately captures the effects of particle size, choice of base liquid, thermal interfacial resistance between the particles and liquid, temperature, etc. This model is a combination of the Maxwell-Garnett (MG) conduction model and the convection caused by the Brownian movement of the nanoparticles, and reduces to the MG model for large particle sizes. The model is in good agreement with data on water, ethylene glycol, and oil-based nanofluids, and shows that the lighter the nanoparticles, the greater the convection effect in the liquid, regardless of the thermal conductivity of the nanoparticles.

scholarly journals Estimation of Effective Thermal Conductivity of Two-Phase Material for Hollow Circular Model

2018 ◽  
Vol 172 ◽  
pp. 02004
Author(s):  
Prateek Kumar Sahu ◽  
Nisha Netam ◽  
Lal Chandra Shah
Keyword(s):  
Thermal Conductivity ◽  
Circular Cylinder ◽  
Effective Thermal Conductivity ◽  
Complex Structure ◽  
Fundamental Property ◽  
Percentage Error ◽  
Phase System ◽  
Two Phase ◽  
Hollow Circular Cylinder ◽  
Circular Model

Two-phase materials are commonly used in engineering application because of its various properties like strength, thermal conductivity, durability and toughness etc. Effective thermal conductivity (ETC) of two-phase material is the fundamental property to predict its thermal performance. Various geometry (spheres, cylinders, irregular particles) have been considered by researchers for calculating ETC of two-phase materials. Due to complex structure, hollow circular cylinder geometry is not reported yet. In this paper, two-dimensional periodic two-phase system, with hollow circular cylinder shape is considered for calculating ETC. In present work unit cell approach method is used to derive collocated parameters model for estimation of ETC. Hollow circular cylinder model with Ψ = 0.2 gives good result for estimating ETC with average percentage error of 6.46%.

Experimental and Theoretical Modeling of the Effective Thermal Conductivity of Rough Steel Spheroid Packed Beds

2003 ◽  
Vol 125 (4) ◽  
pp. 693-702 ◽  
Author(s):  
G. Buonanno ◽  
A. Carotenuto ◽  
G. Giovinco ◽  
N. Massarotti
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Solid Mechanics ◽  
Packed Bed ◽  
Elementary Cell ◽  
Upper And Lower Bounds ◽  
Packed Beds ◽  
The Finite Element Method ◽  
Two Phase ◽  
Experimental Apparatus

The upper and lower bounds of the effective thermal conductivity of packed beds of rough spheres are evaluated using the theoretical approach of the elementary cell for two-phase systems. The solid mechanics and thermal problems are solved and the effects of roughness and packed bed structures are also examined. The numerical solution of the thermal conduction problem through the periodic regular arrangement of steel spheroids in air is determined using the Finite Element Method. The numerical results are compared with those obtained from an experimental apparatus designed and built for this purpose.

Numerical investigation of effective thermal conductivity for two-phase composites using a discrete model

2017 ◽  
Vol 115 ◽  
pp. 1-8 ◽  
Author(s):  
Thomas Oppelt ◽  
Thorsten Urbaneck ◽  
Holger Böhme ◽  
Bernd Platzer
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Numerical Investigation ◽  
Discrete Model ◽  
Two Phase

A HIERARCHICAL MODEL FOR MULTI-PHASE FRACTAL MEDIA

Fractals ◽  
2010 ◽  
Vol 18 (01) ◽  
pp. 53-64 ◽  
Author(s):  
MAOFEI MEI ◽  
BOMING YU ◽  
JIANCHAO CAI ◽  
LIANG LUO
Keyword(s):  
Distribution Function ◽  
Pore Space ◽  
Fractal Dimensions ◽  
Solid Particles ◽  
Two Phase ◽  
Fractal Media ◽  
Proposed Model ◽  
Three Phase ◽  
Multi Phase ◽  
Good Agreement

The size distributions of solid particles and pores in porous media are approximately hierarchical and statistically fractals. In this paper, a model for single-phase fractal media is constructed, and the analytical expressions for area, fractal dimension and distribution function for solid particles are derived. The distribution function of solid particles obtained from the proposed model is in good agreement with available experimental data. Then, a model for approximate two-phase fractal media is developed. Good agreement is found between the predicted fractal dimensions for pore space from the two-phase fractal medium model and the existing measured data. A model for approximate three-phase fractal media is also presented by extending the obtained two-phase model.

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