Thermophysical properties of high porosity metal foams

Bhattacharya, Anandaroop; Calmidi, Varaprasad; Mahajan, Roop L.

doi:10.1016/s0017-9310(01)00220-4

Cited by 992 publications

(431 citation statements)

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“…These plots are linear, showing that flow is indeed in the regime of validity of DarcyÕs law. Multiplying the slope of these lines with the viscosity l of the fluid yields the permeability K. Resulting values for K are given in Table 1 [5,21,[25][26][27]32] are added to the plot after division of reported permeabilities by reported average pore diameters squared.…”

Section: Resultsmentioning

confidence: 99%

“…Evolution of the permeability K normalized by the pore size squared d 2 as a function of the foam density V s . Discrete points are the measured data from the present study (the two symbols correspond to the two different pore size classes that are investigated, i.e., 75 and 400 lm) and data from publications in the literature [5,21,[25][26][27]32]. The lines are predictions according to Eq.…”

Section: Discussionmentioning

confidence: 99%

“…Characteristic foam parameters K and C of Eq. (1) have thus been measured by various authors for nickel foams [22,23] or for ERGÕs cast aluminium foams, at times compressed beforehand by plastic deformation along one direction to improve their heat-transfer characteristics (this, of course, renders the foams anisotropic) [3,5,6,9,16,[24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

“…Bhattacharya et al [26] also adapted the model of Du Plessis et al with a different estimation of the unit cell size, additionally modifying the evaluation of the tortuosity parameter to account for the finite size of nodes in the foam. These authors also found good agreement with their own experimental data.…”

Section: Introductionmentioning

confidence: 99%

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Permeability of open-pore microcellular materials

2005

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Permeability of open-pore microcellular materials

2005

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“…Experimental measurement and modelling [4][5][6][7] have shown that the thermal characteristics of porous metals are a complex interplay between porosity fraction, pore size, surface area and ligament thickness, as this influences both the thermal properties of the porous metal and its permeability with respect to the fluid flowing through it. Whilst some observations appear to be conflicting, there is general agreement that porous metals with higher relative density and small pore sizes have higher thermal conductivities, while foams which are more "open" are likely to perform better in convective heat transfer due to enhanced thermal dispersion or mixing associated with their higher permeability.…”

Section: Introductionmentioning

confidence: 99%

Discrete element modelling of the packing of spheres and its application to the structure of porous metals made by infiltration of packed beds of NaCl beads

Langston

Kennedy

2014

Powder Technology

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Discrete element modelling of the packing of spheres and its application to the structure of porous metals made by infiltration of packed beds of NaCl beads. Powder Technology, Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/34443/7/DEM%20porous%20metals%20-%20Powder %20Technology.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution Non-commercial No Derivatives licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by-nc-nd/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractA numerical model, using the discrete element method, has been developed to quantify specific parameters that are pertinent to the packing behaviour of relatively large, spherical NaCl beads and mixtures of beads of different sizes. These parameters have been compared with porosity and connectivity measurements made on porous aluminium castings made by molten metal infiltration into packed beds of such beads, after removal of the NaCl by dissolution. DEM has been found to accurately predict the packing fraction for salt beads with both monosized and binary size distributions and from this the pore fractions in castings made by infiltration into packed beds of beads could be predicted. Through simple development of the condition for contacting of neighbouring beads, the number of windows linking neighbouring pores, and their size, could also be predicted across a wide range of small bead additions. The model also enables an insight into the mixing quality and changes in connectivity introduced through the addition of small beads. This work presents significant progress towards the delivery of a 2 simulation-based approach to designing preform architectures in order to tailor the resulting porous structures to best suit specific applications. KeywordsDiscrete element method; particle packing; coordination number; porous metals; IntroductionPorous metals exhibit important characteristics which enable them to perform well in heat transfer applications. The high thermal conductivity of solid ligaments, the large surface area to volume ratios and their tortuous flow paths, which generate turbulence and high level-mixing in the cooling fluid, offer the potential for devices made from porous metals (for example high power electronic devices [1,2], heat shields, regenerators for thermal engines and thermal energy storage devices incorporating phase change materials [3]) to be compact, efficient and light weight.Experimental measurement and modelling [4][5][6][7] have sho...

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Quantifying uncertainty sources in the gridded data of sea surface CO₂ partial pressure

et al. 2014

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The bulk uncertainty in the gridded sea surface pCO 2 data is crucial in assessing the reliability of the CO 2 flux estimated from measurements of air-sea pCO 2 difference, because atmospheric pCO 2 are relatively homogeneous and well defined. The bulk uncertainty results from three different sources: analytical error (E m ), spatial variance (r 2 s ), and the bias from undersampling (r 2 u ). Common uncertainty quantification by standard deviation may mix up the different sources of uncertainty. We have established a simple procedure to determine these three sources of uncertainty using remote sensing-derived and field-measured pCO 2 data. E m is constrained by the analytical method and data reduction procedures. r 2 s is derived from the remotely sensed pCO 2 field. r 2 u is determined by spatial variance and the effective number of observations, considering, for the first time, the geometric bias introduced by pCO 2 sampling. This approach is applied to 1 3 1 gridded pCO 2 data collected from the East China Sea. We demonstrate that the spatial distribution of these biases is uneven and that none of them follow the same spatial trend as the standard deviation. r 2 s contributes the most to the uncertainty in gridded pCO 2 data over those grid boxes with good sampling coverage, while r 2 u dominates the total uncertainty in the grid boxes with poor sampling coverage. Application of this procedure to other parts of the global ocean will help to better define the inherent spatial variability of the pCO 2 field and thus better interpolate and/or extrapolate pCO 2 data, and eventually better constrain air-sea CO 2 fluxes.

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Thermophysical properties of high porosity metal foams

Cited by 992 publications

References 39 publications

Permeability of open-pore microcellular materials

Permeability of open-pore microcellular materials

Discrete element modelling of the packing of spheres and its application to the structure of porous metals made by infiltration of packed beds of NaCl beads

Quantifying uncertainty sources in the gridded data of sea surface CO₂ partial pressure

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Thermophysical properties of high porosity metal foams

Cited by 992 publications

References 39 publications

Permeability of open-pore microcellular materials

Permeability of open-pore microcellular materials

Discrete element modelling of the packing of spheres and its application to the structure of porous metals made by infiltration of packed beds of NaCl beads

Quantifying uncertainty sources in the gridded data of sea surface CO2 partial pressure

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Product

Resources

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Quantifying uncertainty sources in the gridded data of sea surface CO₂ partial pressure