Numerical and experimental study of conjugate heat transfer in a horizontal air cavity

Troppová, Eva; Tippner, Jan; Švehlík, Matěj

doi:10.1007/s12273-017-0403-y

Cited by 9 publications

(2 citation statements)

References 20 publications

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“…One of the most effective applications of reflective materials can be found in [28], where the simple application of a reflective panel between a radiator and the perimetral wall (common pattern in residential applications) leads to an energy saving of 3.50% in the worst insulation conditions. Several studies were developed in the past regarding heat reflective insulators and were mainly divided into two groups: numerical approaches, with the aim to be implemented into simulation software [29][30][31][32][33][34][35][36][37][38][39][40][41][42], and experimental approaches to characterize their properties [43][44][45][46][47][48][49]. A research review about heat-reflective materials [50] estimates that about 59% of the studies were concerned with experimental approaches (either field measurement or indoor test rigs) whereas only 41% regarded numerical simulations (e.g., building performance or CFD).…”

Section: Introductionmentioning

confidence: 99%

Reliability Analysis and Economic Evaluation of Thermal Reflective Insulators

Borelli

Cavalletti

et al. 2022

Energies

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High-performance thermal insulators allow a dramatic reduction in the thickness of coatings, thanks to their low thermal conductivity. This study provides an overview about thermal insulation materials, with regards to heat reflective insulators in particular. Then, the numerical investigation method adopted to compute the thermal resistance associated with reflective insulators is introduced. This method has been used in turn to check the accuracy of the declared, measured performance of different, heat-reflective materials on the market. Many manufacturers of reflective insulators were available to provide information and a good agreement between the declared and expected thermal resistance has been found. The choice of a non-experimental approach is meant to check the validity of an already performed test on a reflective insulator using a predictive approach instead of standard, additional testing. Then, the insulation of five typical walls at three different sites in Italy has been simulated, showing that most of heat-reflective materials cannot achieve the maximum required transmittance. Interstitial condensation is likely to occur in specific cases, also because of the aluminum layers inside. The economic analyses showed comparable costs for both heat reflective and traditional insulators, and their cost effectiveness needs to be evaluated case by case.

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Section: Introductionmentioning

confidence: 99%

Reliability Analysis and Economic Evaluation of Thermal Reflective Insulators

Borelli

Cavalletti

et al. 2022

Energies

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“…Amghar et al [22] reported that spacing between the baffles improves the heat transfer by forced convection during the turbulent flow with transverse baffles inside a horizontal channel. Eva et al [23] studied combined conduction, convection and radiation heat transfer in a closed horizontal airy cavity, where its thickness and inner surface emissivity are tested with constant heat flux. They found that the increase in cavity thickness decreases the heat flux.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of Convection Heat Transfer in an Enclosure With a Vertical Heated Block and Baffles

Aun

Ghadhban

Jehhef

2021

Journal of Thermal Engineering

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In this study, the natural and forced convection heat transfer in an enclosure with vertical heated block and baffles are experimentally and numerically investigated. The enclosure walls are kept as adiabatic, and the heating block contains extended baffles and receives heat flux. The effect of heat flux, Reynolds number and baffle configuration on the heat transfer characteristics and flow behaviour inside the enclosure is examined. The configuration parameter for natural and forced convection involves three heating block models, namely, block without baffle (plain), block with baffles and block with partially cut baffles. The widths of baffles are 2.5, 5 and 10 cm for the block with baffle case, and the width of partially cut baffle is 5 cm. The heat flux (q) ranges from 240 w/m 2 to 1425 w/m 2 for all the models. The Reynolds number (Re) ranges from 5650 to 15950 for forced convection heat transfer. In the numerical part, a finite volume method (via Ansys Fluent) is used to solve the governing equations. Result shows that the increase in baffle width has no remarkable effect on the heat transfer, and the partially cut baffles provide an enhancement of approximately 30% compared with the plain heating block. The baffle cases have an evident effect in reducing the block surface temperature by approximately 11% compared with the plain case at Re = 0 and q = 240 w/m 2 . Empirical correlations for the block with baffles are obtained for each heat flux to predict the average Nusselt number.

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Numerical simulation of heat transfer in a roof assembly with reflective insulation and radiant barrier

Ashhar

Haw

2020

Build. Simul.

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Numerical and experimental study of conjugate heat transfer in a horizontal air cavity

Cited by 9 publications

References 20 publications

Reliability Analysis and Economic Evaluation of Thermal Reflective Insulators

Reliability Analysis and Economic Evaluation of Thermal Reflective Insulators

Experimental and Numerical Investigation of Convection Heat Transfer in an Enclosure With a Vertical Heated Block and Baffles

Numerical simulation of heat transfer in a roof assembly with reflective insulation and radiant barrier

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