Cellular ceramics produced by rapid prototyping and replication

Ortona, Alberto; D’Angelo, Claudio; Gianella, Sandro; Gaia, Daniele

doi:10.1016/j.matlet.2012.04.050

Cited by 93 publications

(44 citation statements)

References 8 publications

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“…For example, by adjusting only the flow direction, the ratio between filtration coefficient and pressure drop could be improved by up to 18%. 6) Under typical process conditions for continuous aluminum filtration, the fluid flow inside all investigated structures remained steady, except for the artificial foam at very low porosity, for which average interstitial velocity fluctuations up to 7.5% were detected. The transition to unsteady flow was observed to take place when the contribution of inertial losses amounted to approximately 60% of the total pressure drop and was more pronounced for realizations with thicker joints.…”

Section: Summary Conclusion and Outlookmentioning

confidence: 84%

“…Further, flexibility in the design of the geometry can be achieved by using additive manufacturing of the precursors. [6] The present investigation was carried out in order to facilitate the design of improved filter geometries. In order to achieve this objective, 25 realizations of a periodic artificial foam structure were investigated, whose porosity and material distribution between the struts and the joints were manipulated to a certain extent.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Foam Morphology on Effective Properties Related to Metal Melt Filtration

et al. 2017

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In this article, a numerical study on the sensitivity, related to the performance of open-cell foams used for the depth filtration of liquid metals, on two characteristic morphological properties is presented. Therefore, simulations of fluid flow and particle transport inside an artificial foam structure are carried out, whose porosity and strut shape is varied within a certain expected range. For comparison purposes, however, the simulations are also performed for three typical ceramic foam filters (CFF) with pore densities of 20 and 30 PPI, whose geometries are obtained from CT scans. In order to allow for a comparison between the different structures, a reference length is introduced that relies upon the actual ratio of pores per volume. The evaluation is mainly based on the comparison of the hydraulic tortuosity, the viscous and the inertial permeability coefficients as well as the initial filtration coefficient for alumina inclusions, with their size ranging from of 10 to 40 mm at process conditions typically encountered during the aluminum filtration. It is shown that the ratio of filtration coefficient and pressure drop increases with the porosity, while the material distribution between the struts and the joints is less influential. Finally, the article also provides information on the anisotropy of CFFs and on the transition behavior from steady to unsteady flow in open-cell foams.

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Section: Summary Conclusion and Outlookmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Influence of Foam Morphology on Effective Properties Related to Metal Melt Filtration

et al. 2017

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“…All templates were 3D printed with the same strut diameter Ds¼0.4 mm using 3DLPrinter-HD 2.0 (Robot Factory S.r.l., It), with a resolution of 10 and 50 mm in vertical and horizontal axes, respectively. Replica technique was used to convert the polymeric structures into ceramic [30]: the templates were impregnated in a slurry containing bimodal α-SiC particles dispersed in an organic solvent by ball milling for 12 h and then, after adding a polymer binder, for further 36 h [4]. The fine and coarse SiC powders present an average particle size of 1.4 mm D50 and 5 mm D50, measured by laser diffraction, respectively.…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

“…Among the potential ceramic materials which can be shaped in a cellular architecture, silicon infiltrated SiC (SiSiC) is particularly interesting due to its outstanding mechanical and thermal properties at high temperatures. SiSiC porous periodic architectures have recently been produced using replica technique of lattice structures obtained from polymeric templates made by 3D printing followed by reactive infiltration of silicon [4].…”

Section: Introductionmentioning

confidence: 99%

Early-stage oxidation behavior at high temperatures of SiSiC cellular architectures in a porous burner

Rezaei

Haussener

Gianella

et al. 2016

Ceramics International

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a b s t r a c tEarly stage oxidation behavior of SiSiC cellular lattices with different cell types was studied at 1400°C in two different environments: a porous burner and an electric furnace with stagnant air. Oxidation and silicon alloy bead formation were observed and identified as the most important factors affecting the integrity of the structures. Low melting temperature silicon-based alloys formed from the material due to presence of impurities. Having lower melting point than the thermal tests temperature, the beads exuded from the microstructure leaving pores in the substrate material and leading to enhanced oxidation on the surface. Moreover, it was observed that different lattice architectures lead to different oxidation behavior on the struts as a result of the changing gas flow paths inside each ceramic architecture.

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“…We present results obtained for a model geometry. Structured, lattice-type porous media are of interest in a wide variety of applications (porous burners, heat exchangers, or lightweight structures), provide interesting test media with well-defined structures, and can easiest be implemented as materials by design [19].…”

Section: Introductionmentioning

confidence: 99%

Numerical quantification of coupling effects for radiation-conduction heat transfer in participating macroporous media: Investigation of a model geometry

Perraudin

Haussener

2017

International Journal of Heat and Mass Transfer

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a b s t r a c tRadiative-conductive heat transfer in porous media is usually investigated by decoupling the heat transfer modes and solving the volume-averaged continuum equations using effective transport properties. However, both modes are naturally coupled and coupling effects might significantly affect the results. We aim at providing quantitative understanding of the coupling effects occurring in a model geometry. This is an important first step towards improving the accuracy of heat transfer predictions in engineering applications.We developed a numerical method using a structured mesh, cell centered finite volumes and Monte Carlo ray tracing techniques in order to simulate the 3-dimensional and unsteady coupled radiativeconductive heat transfer in semitransparent macroporous media. We have optimized the numerical method with regards to memory and computational requirements leading to optimal performance and allowing to perform a parameter variation study for various steady state cases.We conducted a parameter study considering different optical and thermal material properties and boundary conditions in order to quantify the coupling effect between conduction and radiation, and to demonstrate its dependencies. In terms of thermal properties, it was found that the ratio of bulk thermal conductivities is governing the coupling effect. A distinct peak at a given conductivity ratio was found. The influence of optical properties is discussed in details. It was found that a significant coupling effect exists, reaching up to 15% of the total thermal heat flux.The verified modeling framework in conjunction with our non-dimensionalization offers a tool to investigate the importance of radiation-conduction coupling in a quantitative manner. It is an important step towards understanding the detailed mechanisms of radiation and conduction coupling and provides engineering guidelines on the importance of these effects.

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Cellular ceramics produced by rapid prototyping and replication

Cited by 93 publications

References 8 publications

Influence of Foam Morphology on Effective Properties Related to Metal Melt Filtration

Influence of Foam Morphology on Effective Properties Related to Metal Melt Filtration

Early-stage oxidation behavior at high temperatures of SiSiC cellular architectures in a porous burner

Numerical quantification of coupling effects for radiation-conduction heat transfer in participating macroporous media: Investigation of a model geometry

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