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Showing 1 to 20 of 61 for “"Effective Thermal Conductivity"”.
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Effective thermal conductivity measurements relevant to deep borehole nuclear waste disposal
The objective of this work was to measure the effective thermal conductivity of a number of materials (particle beds, and fluids) proposed for use in and around canisters for disposal of high level nuclear waste in deep boreholes. This information is required to insure that waste temperatures will …
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Effective thermal conductivity of binary mixed materials with fissile components - an empirical approach
An empirical approach to determine the effective thermal conductivity of a binary mixed material with heat generation is presented. Analysis was carried out for a steady state problem with spherical geometry to develop an expression for the effective thermal conductivity for the spherical pebble …
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Characterisation of the effective thermal conductivity in the near wall region of a packed pebble bed
The effective thermal conductivity is an important parameter that is representative of the overall heat transfer in a packed bed of spheres. An accurate prediction of the effective thermal conductivity is necessary for the design and analysis of packed pebble bed gas-cooled reactors, especially …
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Application of the Transient Hot-Wire Technique for Measurement of Effective Thermal Conductivity of Catalyzed Sodium Alanate for Hydrogen Storage
… almost 5 wt% of hydrogen. In this research, the effective thermal conductivity, k, of a sample of titanium-doped sodium alanate is studied over a range of operating conditions pertinent to practical on-board hydrogen storage. A transient technique employing a platinum hot-wire is used to make the …
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A comprehensive fractal approach in determination of the effective thermal conductivity of gas diffusion layers in polymer electrolyte membrane fuel cells
… fuel cell industry is to produce the efficient thermal and water management for accurate determination of the effectiveness thermal conductivity of gas diffusion layers (GDL) used in polymer electrolyte membrane fuel cells (PEMFC‟s). This is one of the factors affecting the durability of a fuel …
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Cálculo da condutividade térmica efetiva de meios heterogêneos com múltiplas escalas via homogeneização reiterada e elementos finitos
… is the reason why one proposes to calculate an effective thermal conductivity of a heterogeneous medium with multiple scales. In the present work, a numerical-analytical methodology is developed, based on the variational calculus, the theory of reiterated homogenization and the finite element …
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The effect of abrasive properties on the surface integrity of ground ferrous materials.
The effect of the thermal properties of alumina and CBN abrasives on workpiece temperatures in grinding was investigated. A review of the literature revealed a lack of knowledge of the thermal properties of CBN limiting the accuracy of theoretical predictions of the heat conduction in CBN grinding. …
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Effect of Aerogel on the Thermal Performance of Corrugated Composite Sandwich Structures
… the commercial sector, can be bulky and ineffective when considering their volume. Aerogels are excellent insulators, exhibiting low thermal conductivities and low densities with a porosity of around 95%. Such characteristics make aerogels effective in decreasing conductive heat transfer …
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Analytical and numerical studies of heat and moisture transfer through porous insulation
… water vapor transfer in flat-slab and round-pipe thermal insulations. The model is validated by comparing its predictions with available experimental data. The effective thermal conductivity of the insulation in the presence of condensation depends on seven design and operating variables. The …
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Radiative transfer and thermal performance levels in foam insulation boardstocks
The validity of predictive models for the thermal conductivity of foam insulation is established based on the fundamental geometry of the closed-cell foam. The extinction coefficient is experimentally and theoretically determined; the theoretical prediction based on measured geometrical properties …
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Thermal Conductivity of Fiber-Reinforced Lightweight Cement Composites
… a multiscale mathematical model to predict the effective thermal conductivity (ETC) of fiber-reinforced lightweight cement composites. At various stages in the development of the model, the results are compared to experimental values and the model is calibrated when appropriate. Additionally at …
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Effective Thermal Properties of Granular Porous Media: A Numerical Study using Lattice Blotzmann Methods
… earth, and biological sciences, to name a few. Effective thermal conductivity in granular porous media is a function of morphological features of the medium such as grain shape, grain size, and geometrical structure. Thermal contact resistance can also affect heat conduction due to topological …
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Nanoscale Thermal Transport at Solid -Liquid Interfaces
… transient absorption measurement to probe thermal transport in Au-core polymer-shell nanoparticles. The addition of an organic co-solvent to the suspension causes the polystyrene component of the polymer shell to swell and this change in the microstructure of the shell increases the …
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Development of a Numerical Solver for Phase-Change and Two-Phase Flow in Porous Media
Porous media are used in several thermal management systems, such as loop-heat-pipes, to control the temperature of electronics and other components. It is important to understand the mechanisms of flow and phase-change in porous media to better control/increase the performance of those systems. In …
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A deviational Monte Carlo formulation of ab initio phonon transport and its application to the study of kinetic effects in graphene ribbons
… a geometry used to experimentally measure the thermal conductivity of graphene. Our results show that the effective thermal conductivity of ribbons decreases monotonically as either the length or the width of the ribbon decreases. We also show that at room temperature the error introduced by …
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Optothermal Characterization of Nanoparticle Infused Aerogels
… to achieve super insulating and transparent opto-thermal properties. By incorporating nanoparticle solutions within the silicon dioxide (SiO₂) aerogel during the sol-gel process, unique monolithic samples were fabricated and opto-thermally characterized. The pure silica and nanoparticle infused …
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Gas Fired Fluidized Beds
… profiles in the axial direction. The concept of Effective Thermal Conductivity is discussed, and bed conductivities are re-defined bearing in mind the contribution of particle recirculation. Experiments have been performed with particle sizes ranging from 0.6 mm to 1.4 mm diameter. Results are …
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