Coordination measurements in compacted NaCl irregular powders using X-ray microtomography

Marmottant, A.; Salvo, Luc; Martín, Christophe; Mortensen, Alicja

doi:10.1016/j.jeurceramsoc.2008.03.041

Cited by 35 publications

(23 citation statements)

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“…In general, the dissolution time decreases as the bead size and compaction pressure increase. Higher compaction pressures result in increased connectivity of the salt bead structure (both in terms of the co-ordination number and the contact area [17]) and larger beads lead to larger channels, allowing easier ingress of water and egress of NaCl and increased rates of dissolution. Infiltrating the preform at higher pressure results in an increase in the time required to remove the NaCl.…”

Section: Resultsmentioning

confidence: 99%

Characterisation and Mechanical Testing of Open Cell Al Foams Manufactured by Molten Metal Infiltration of Porous Salt Bead Preforms: Effect of Bead Size

Jinnapat

Kennedy

2012

Metals

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Preforms made from porous salt beads with different diameters (0.5-1.0, 1.4-2.0 and 2.5-3.1 mm) have been infiltrated with molten Al to produce porous structures using pressure-assisted vacuum investment casting. Infiltration was incomplete for preforms with high densities. At higher infiltration pressures, penetration of molten Al occurred into beads of all sizes and was predicted using a simple model. The yield strength of the porous structures increased with increasing density and decreasing pore (bead) size. Despite the non-optimum distribution of metal in the porous structure, due to partial infiltration within the beads, the magnitude and density dependence of the yield stress were comparable with those for pure Al foams reported in similar studies. The structural efficiency was improved for structures produced at lower infiltration pressure, where the metal is predominantly distributed in the cell walls. The rate of salt dissolution from the preforms was high, in particular for high density preforms, large beads and preforms infiltrated at low pressures, owing to the ability of the porous beads to collapse as well as dissolve.

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Section: Resultsmentioning

confidence: 99%

Characterisation and Mechanical Testing of Open Cell Al Foams Manufactured by Molten Metal Infiltration of Porous Salt Bead Preforms: Effect of Bead Size

Jinnapat

Kennedy

2012

Metals

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“…Fig 3 shows snapshots from the Aviso software showing the output after separation. The number of large particles sampled was at least 1000 and exceeded that used in a similar study where the sample size was deemed to be sufficient for reliable statistics [18]. An effect of vessel size is observed, with an increase in packing fraction from 0.56 to nearly 0.59 as the vessel to bead size ratio increases from 8 (for 18 mm) to nearly 18 (for 40 mm).…”

Section: Equationmentioning

confidence: 91%

“…The coordination number for cast porous metal structures was determined from CT images and image analysis using Aviso Fire software. Since the pores in the casting are connected, they were first thresholded and then separated using a watershed algorithm similar to those used in [17,18]. From this, the volume of the object was determined, along with the x, y, z co-ordinates for the centroid and the radius of a sphere with equivalent volume.…”

Section: Equationmentioning

confidence: 99%

“…The effect of a distribution in particle size (in this case a standard deviation of roughly 10%) for the "monosized" case is unlikely to enhance the packing behaviour, with benefits only thought to be likely for deviations greater than 30% [18,27].…”

Section: Overview Of Cast Porous Metal Structuresmentioning

confidence: 99%

“…Whilst DEM has been used to model the packing of monosized particle and binary mixtures and compare the predictions with experimental measurements [14][15][16][17] and has been applied to the packing of monosized NaCl particles that formed the basis for a preform to make porous Al [18], previous studies have not combined these elements and applied them to full-scale modelling of porogen packing and then compared the modelling predictions to structural parameters measured from porous metals made by infiltration of these packed structures.…”

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confidence: 99%

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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

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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Mechanistic Studies of Compacted and Sintered Rock Salt

Swanson

Böhme

Günster

2016

Processing, Properties, and Design of Advanced Ceramics and Composites: Ceramic Transactions

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Coordination measurements in compacted NaCl irregular powders using X-ray microtomography

Cited by 35 publications

References 40 publications

Characterisation and Mechanical Testing of Open Cell Al Foams Manufactured by Molten Metal Infiltration of Porous Salt Bead Preforms: Effect of Bead Size

Characterisation and Mechanical Testing of Open Cell Al Foams Manufactured by Molten Metal Infiltration of Porous Salt Bead Preforms: Effect of Bead Size

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

Mechanistic Studies of Compacted and Sintered Rock Salt

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