An experimental study on the thermal conductivity of aluminium foams by using the transient plane source method

Solórzano, E.; Reglero, J.A.; Rodríguez‐Pérez, Miguel Ángel; Lehmhus, Dirk; Wichmann, Manfred; Saja, J.A. de

doi:10.1016/j.ijheatmasstransfer.2007.11.062

Cited by 153 publications

(78 citation statements)

References 30 publications

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“…Metal foams and sponges are versatile materials (see for example [1] and [2]) that have a number of thermal applications in regenerators, air-conditioning systems, gas turbines, electronic cooling and chemical reactors [3][4][5][6]. Their main advantage is their high specific area which enhances the heat transfer and permits miniaturization of the thermal system.…”

Section: Introductionmentioning

confidence: 99%

“…The porosity ( , the inverse of the amount of solid material) is well defined and easily measured, it only requires that the mass and volume are known. The effective thermal conductivity has been found to be highly sensitive to the porosity, increasing as the porosity decreases [5][6][7][8][13][14][15]. The effect of pore size on ETC is less significant, and generally no noticeable effect of pore size has been reported [5,8,9,15], provided the pore size is below a certain value shown to be 4 mm diameter in closed cell polymer foams which is sufficient to suppress convection [3,16,17].…”

Section: Introductionmentioning

confidence: 99%

“…The most common type of transient measurement is the Transient Plane Source technique (TPS) [25,26], where a single element acts as both temperature sensor and heat source . It has been widely used to measure the ETC of porous materials [6,12,23]. The TPS element is positioned between two samples with similar characteristics and measures the instantaneous temperature gradient with time [6,25,26].…”

Section: Introductionmentioning

confidence: 99%

“…It has been widely used to measure the ETC of porous materials [6,12,23]. The TPS element is positioned between two samples with similar characteristics and measures the instantaneous temperature gradient with time [6,25,26]. The main advantages of this approach are that the tests are easy and rapid, and it is possible to measure a wide range of thermal conductivities [6,10].…”

Section: Introductionmentioning

confidence: 99%

“…The TPS element is positioned between two samples with similar characteristics and measures the instantaneous temperature gradient with time [6,25,26]. The main advantages of this approach are that the tests are easy and rapid, and it is possible to measure a wide range of thermal conductivities [6,10]. The analysis can be complex and quantification of uncertainty difficult [10].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

The effective thermal conductivity of open cell replicated aluminium metal sponges

Abuserwal

Luna

Goodall

et al. 2017

International Journal of Heat and Mass Transfer

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The effective thermal conductivity of open cell replicated aluminium metal sponges

Abuserwal

Luna

Goodall

et al. 2017

International Journal of Heat and Mass Transfer

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Heat Transfer in Polypropylene‐Based Foams Produced Using Different Foaming Processes

et al. 2009

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This paper presents the characterization of the cellular structure and thermal conduction behaviour of polypropylene foams produced using different foaming processes, with the aim of selecting the best possible PP foam thermal insulator. Thermal conductivity results have shown that the global heat transfer behaviour is controlled by the relative density. For relative densities higher than 0.2, thermal conductivity differences were insignificant, the data being predicted by the mixture's rule and Russell's model. In the low density range, all of the proposed models underestimated the overall conductivity, the effect of the processing method being more significant, slight differences being observed between foams produced by extrusion and those produced by gas dissolution with higher cell sizes and anisotropies. Foams with finer cellular structures showed to be better insulating materials.

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Lattice Monte Carlo and Experimental Analyses of the Thermal Conductivity of Random‐Shaped Cellular Aluminum

et al. 2009

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Aluminum foams (cf. Fig. 1) constitute a group of innovative materials with interesting properties such as high specific strength, [1] acoustic and structural damping, [2] controlled energy absorption, [3] and thermal insulation. [4] Their big potential lies within multifunctional applications where combinations of their properties yield symbiotic advantages. Among others, the effective thermal conductivity is of particular interest for applications in heat sinks, [5] heat exchangers, [6,7] or thermal insulation. [4] In the analysis of the thermal conductivity we should first consider that the heat transfer is brought about due to three different mechanisms: thermal radiation, thermal convection, and thermal conduction. Nevertheless it has been demonstrated [8,9] that the influence of thermal radiation on the effective thermal conductivity of porous metals, especially at temperatures below 700 K is low and its contribution to the effective thermal conductivity can be disregarded within these studies. On the other hand, gas movement through the interconnected porosity of the M-Pore structure (i.e., natural convection) could partially contribute to its effective thermal conductivity [10] but the contribution in the case of open-cell aluminum foams is estimated to be lower than 10%. The effect of thermal convection within the closed-cell Alporas structures is small and can be neglected. Therefore, bulk movement of gas through interconnected porosity is disregarded in this work and accordingly the validity of the results is restricted to cases where heat transfer occurs predominantly by thermal conduction. The thermal energy flux _ Q is then given by Fourier's lawwhere A is the control surface and DT/Dx is the temperature gradient. Materials and Methods MaterialsTwo different kinds of aluminum foams have been studied in this work. Alporas foams produced in the molten state by direct addition of pure calcium (to produce the melt thickening) and TiH 2 (to foam the thickened melt) [11] present an apparent closed-cell structure and exhibit typical porosities ranging from 0.90 to 0.92. These materials are typically classified as a closed-cell material and it is assumed that gas is occluded (i.e., it is a noncontinuous phase). On the other hand M-Pore aluminum sponges produced by infiltrating vacuum replication [12] present slightly higher porosities (0.92-0.94) and an open-cell structure, typical of the original polyurethane foams used as a basis in the process. Micro-computed TomographyAs a first step, CT scans (cf. Fig. 2) of open-celled M-Pore aluminum sponges and closed-celled Alporas aluminum foams are conducted. A micro-CT system (mCT) composed by a micro-focus 150 kV X-ray source with a tungsten target and a flat panel detector C7942 (120 Â 120 mm 2 , 2240 Â 2368 pixel 2 , pixel-size 50 mm) was used to measure the density profile of each sample. A 100 kV filament voltage and a current of 100 mA were used in all cases. Using a source-sample distance of 200 mm and a source-detector distance of 400 mm, we achieve a ma...

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An experimental study on the thermal conductivity of aluminium foams by using the transient plane source method

Cited by 153 publications

References 30 publications

The effective thermal conductivity of open cell replicated aluminium metal sponges

The effective thermal conductivity of open cell replicated aluminium metal sponges

Heat Transfer in Polypropylene‐Based Foams Produced Using Different Foaming Processes

Lattice Monte Carlo and Experimental Analyses of the Thermal Conductivity of Random‐Shaped Cellular Aluminum

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