Monitor and control test room for investigating thermal performance of panels incorporating phase-change material

Abstract. This article aims to present equipment designed and developed to study the effective thermal conductivity of composite panels. The composite panel used is a rigid polyurethane foam covered with a layer of aluminum on both sides. The panel is mounted in the test chamber equipped with several sensors and actuators connected via an Arduino platform. Tests have been carried out by applying heat to impose various interior temperatures. Sensors at different locations are used to monitor and record temperatures in and around the composite panel during heating and natural cooling. A model, based on the Fourier equations of thermal conduction and natural convection heat transfer for the steady state, was developed to assess the effective thermal conductivity. The performance of the system was confirmed using temperature signals through the panels for thermal characterization of composite materials. The determined effective thermal conductivity obtained was in agreement with the experimental values reported in the technical data sheets with relative deviations of less than 10 %.

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Convective Heat Transfer Enhancement With Nanofluids: The Effect of Temperature-Variable Thermal Conductivity

ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, Volume 2 ◽

10.1115/esda2010-25235 ◽

2010 ◽

Author(s):

Sezer O¨zerinc¸ ◽

Almıla G. Yazıcıog˘lu ◽

Sadık Kakac¸

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

Thermal Conductivity ◽

Heat Transfer Enhancement ◽

Forced Convection ◽

Convection Heat Transfer ◽

Thermal Dispersion ◽

Convection Heat ◽

Transfer Enhancement ◽

Experimental Values

A nanofluid is defined as the suspension of nanoparticles in a base liquid. Studies in the last decade have shown that significant amount of thermal conductivity and heat transfer enhancement can be obtained by using nanofluids. In the first part of this study, classical forced convection heat transfer correlations developed for pure fluids are used to predict the experimental values of heat transfer enhancement of nanofluids. It is seen that the experimental values of heat transfer enhancement exceed the enhancement predictions of the classical correlations. On the other hand, a recent correlation based on the thermal dispersion phenomenon created by the random motion of nanoparticles predicts the experimental data well. In the second part of the study, in order to further examine the validity of the thermal dispersion approach, a numerical analysis of forced convection heat transfer of Al2O3/water nanofluid inside a circular tube in the laminar flow regime is performed by utilizing single phase assumption. A thermal dispersion model is applied to the problem and variation of thermal conductivity with temperature and variation of thermal dispersion with local axial velocity are taken into account. The agreement of the numerical results with experimental data might be considered as an indication of the validity of the approach.

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Effective Thermal Conductivity for Combined Radiation and Free Convection in an Optically Thick Heated Fluid Layer

Journal of Heat Transfer ◽

10.1115/1.3244403 ◽

1981 ◽

Vol 103 (1) ◽

pp. 114-120 ◽

Cited By ~ 5

Author(s):

M. Epstein ◽

F. B. Cheung ◽

T. C. Chawla ◽

G. M. Hauser

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Free Convection ◽

Effective Thermal Conductivity ◽

Radiative Heat ◽

Fluid Layer ◽

Convection Heat Transfer ◽

Turbulent Heat ◽

Free Convection Heat ◽

Heated Fluid

The effective thermal conductivity for radiative heat transfer within an optically thick fluid layer undergoing high Rayleigh number convection is derived. This result is combined with available “pure” free-convection heat-transfer correlations to obtain closed-form analytical descriptions of the gross properties of a radiating fluid layer heated internally or from below. These simple solutions compare favorably with recent work in which the governing energy equation incorporating both turbulent heat transport and thermal radiation is solved numerically.

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Thermal Characterization of Aluminum and Steel Foams

Volume 3: Design, Materials and Manufacturing, Parts A, B, and C ◽

10.1115/imece2012-85609 ◽

2012 ◽

Author(s):

James D. Playford ◽

S. Midturi ◽

S. B. Pidugu

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Accurate Determination ◽

Thermal Characterization ◽

Metal Foams ◽

Published Data ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Energy Absorbers

Metallic foams are a new class of ultra-lightweight materials with potential applications in such industries as automobile, aerospace, and energy industries. These materials when realized in product form can serve as efficient heat exchanges, energy absorbers, and thermal protective and hydrogen storage devices. Accurate determination of thermal conductivity and understanding of heat transfer characteristics is important in designing such products incorporating metal foams. The present research characterizes the effective thermal conductivity and heat transfer characteristics of DUOCEL AL 6106-T6 and Stainless Steel 314 open cell foams by experiments at near room temperature conditions. The effective thermal conductivity of these materials has been determined experimentally. Thermal conductivity of metal foams increased with increasing mechanical stress. The effect of porosity on the thermal conductivity of ERG supplied aluminum and NASA-GRC supplied SS 314 are also studied and compared with the published data in literature, however, in our studies systematic dependency of porosity is not observed. Experiments also conducted to quantify forced convective heat transfer characteristics under laminar flow conditions. Heat transfer coefficient increases with increased Reynolds number but results are not conclusive in case of natural convection.

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Processing and thermal characteristics of human hair fiber-reinforced polymer composites

Polymers and Polymer Composites ◽

10.1177/0967391119872399 ◽

2019 ◽

Vol 28 (4) ◽

pp. 252-264

Author(s):

Bishnu Prasad Nanda ◽

Alok Satapathy

Keyword(s):

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Human Hair ◽

Thermal Characteristics ◽

Thermal Characterization ◽

Fiber Reinforced Polymer Composites ◽

Mathematical Correlation ◽

Low Thermal Expansion ◽

Hair Fiber

Human hair is a biofiber having an exceptional chemical composition, higher strength in tension, and slow decomposition rate. In the present work, composites are fabricated by simple hand layup technique with epoxy matrix and different proportions of hair fiber (0, 5, 10, 15, and 20 wt%). Physical, mechanical, microstructural, and thermal characterization of the composite samples has been done by following the proper ASTM standards. A theoretical model has been developed to predict the effective thermal conductivity of the composite. Based on this model, a mathematical correlation between the effective thermal conductivity of the composite and the fiber content is developed. The results obtained from this correlation are in good agreement with the experimental data. This study explores the possibility of fabricating a class of epoxy composites with higher mechanical strength, superior insulation capability, improved glass transition temperature, and a low thermal expansion coefficient.

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Lattice Boltzmann Modeling of the Effective Thermal Conductivity for Complex Structured Multiphase Building Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1119.694 ◽

2015 ◽

Vol 1119 ◽

pp. 694-699 ◽

Cited By ~ 2

Author(s):

Mazhar Hussain ◽

Shakeel Ahmad ◽

Wen Quan Tao

Keyword(s):

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Lattice Boltzmann ◽

Building Materials ◽

Present Model ◽

High Efficiency ◽

Theoretical Models ◽

Random Generation ◽

Proposed Model ◽

Experimental Values

The effective thermal conductivity is an important parameter used to predict the thermal performance analysis of complex structured porous building materials. The observation of porous structure of building materials on REV (representative elementary volume) scale showed that pores can be classified into meso and macro pores. In contrast to the traditional models usually used for the (macro-meso) pore connection , a new numerical random generation macro-meso pores (RGMMP) method, based on geometrical and morphological information acquired from measurements or experimental calculations, is proposed here. Along with proposed structure generating tool RGMMP a high efficiency LBM, characterized with the energy conservation and appropriate boundary conditions at numerous interfaces in the complex system, for the solution of the governing equation is described which yields a powerful numerical tool to obtain accurate solutions. Then present model is validated with some theoretical and experimental values of effective thermal conductivity of typical building materials. The comparison of present model and experimental results shows that the proposed model agrees much better with the experimental data than the traditional theoretical models. Therefore, the present model is not limited to the described building materials but can also be used for predicting the effective thermal conductivity of any type of complex structured building materials.

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