Search results for "Effective thermal conductivity"

showing 4 items of 4 documents

Investigation of Effective Thermal Conductivity Aluminum Foams

2012

Abstract The study on the heat transfer mechanisms through the aluminium foam with a fluid in void cells of that foam was reported in this paper. Based on laboratory experiments, the effective thermal conductivity coefficient values were found for various type aluminum foams which had been filled up with a gas or a liquid. The significant effects were observed from porosity as well as from metal and fluid properties on the heat transfer capacity in a foam-fluid system. The convective heat transfer phenomenon was identified to occur in the foam cellular space. That phenomenon affected the effective thermal conductivity much more for liquid-filled foams than for gas-filled foams.

Void (astronomy)Materials scienceConvective heat transferchemistry.chemical_elementGeneral MedicineMetal foameffective thermal conductivityOpen cell metal foamMetalThermal conductivitychemistryAluminiumheat transfer mechanismsvisual_artHeat transfervisual_art.visual_art_mediumComposite materialPorosityEngineering(all)Procedia Engineering
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Thermal response test analysis for U-pipe vertical borehole heat exchangers under groundwater flow conditions

2021

[EN] Conventional models used in the analysis of thermal response test data only consider conduction as heat transfer mechanism. In cases where presence of groundwater is detected, convection heat transmission plays an important role, so its influence must be determined in the calculation of the effective thermal conductivity, usually overestimated in these situations, increasing its value the higher the power injected and the time elapsed. In this work, based on the data collected in a borehole located at UPV (Valencia) in which have been carried out three thermal response tests with different characteristics, has been implemented a variation of the finite line source model introducing an …

060102 archaeologyGroundwater flowRenewable Energy Sustainability and the Environment020209 energyBoreholeThermal response test (TRT) analysis06 humanities and the arts02 engineering and technologyMechanicsThermal conductionLine sourceGround water advectionUndisturbed ground temperature recoveryThermal conductivityThermal response testHeat transferHeat exchangerMAQUINAS Y MOTORES TERMICOS0202 electrical engineering electronic engineering information engineeringEnvironmental scienceEffective thermal conductivity0601 history and archaeologyBorehole thermal resistanceGeothermal heat exchanger
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HEAT FLUX IN SUPERFLUID TRANSITION AND IN TURBULENT HELIUM COUNTERFLOW

Normal fluid profileRadial flow Vortex diffusionTwo-fluid modelHelium 4Ballistic regimeInhomogeneous vortex tangles.lambda TransitionHeat transferQuantized vorticeEffective thermal conductivityTurbulent superfluid helium ( He II)One-fluid modelExtended Irreversible ThermodynamicEntrance regionSettore MAT/07 - Fisica MatematicaLongitudinal flow
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Effective thermal conductivity of superfluid helium in short channels

2014

The aim of this paper is to explore how the effective thermal conductivity of small channels filled with superfluid helium II in the laminar regime separates from the classical Landau expression as the channel becomes shorter. The Landau expression is valid for fully developed Poiseuille flow for the normal component, and therefore is suitable for long channels. By taking into account entrance effects, we show a transition from a heat flux proportional to ∆T /l (Landau regime) for long channels, to a heat flux proportional to l^(1/3) (∆T /l)^(2/3) for short channels.

Entrance lengthEffective thermal conductivitySuperfluid heliumSettore MAT/07 - Fisica MatematicaPoiseuille flow
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