Permeability and thermal conductivity of porous metallic matrix hydride compacts

Bershadsky, E.; Josephy, Y.; Ron, M.

doi:10.1016/0022-5088(89)90534-1

Cited by 39 publications

(8 citation statements)

References 6 publications

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“…This fragmentation process is essential to achieving fast hydriding kinetics, because the process exposes fresh chemically active surfaces [6], but the fragmented nature of metal hydride particles inhibits hydriding heat dissipation [7]. Expanded graphite [8,9,10] and metal [11,12,13] additives composited with metal hydrides can enhance heat dissipation during the hydriding process, but these chemically inactive materials are parasitic to hydrogen storage density and permeability. In contrast, fragmented hydride packings exhibit high hydrogen storage density and permeability, but the dependence of effective thermal conductivity on the packed structure of hydride powders is not understood well.…”

Section: Introductionmentioning

confidence: 99%

Models for metal hydride particle shape, packing, and heat transfer

Smith

Fisher

2012

International Journal of Hydrogen Energy

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A multiphysics modeling approach for heat conduction in metal hydride powders is presented, including particle shape distribution, size distribution, granular packing structure, and effective thermal conductivity. A statistical geometric model is presented that replicates features of particle size and shape distributions observed experimentally that result from cyclic hydride decreptitation. The quasi-static dense packing of a sample set of these particles is simulated via energy-based structural optimization methods. These particles jam (i.e., solidify) at a density (solid volume fraction) of 0.665 ± 0.015 -higher than prior experimental estimates. Effective thermal conductivity of the jammed system is simulated and found to follow the behavior predicted by granular effective medium theory. Finally, a theory is presented that links the properties of bi-porous cohesive powders to the present systems based on recent experimental observations of jammed packings of fine powder. This theory produces quantitative experimental agreement with metal hydride powders of various compositions.

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Section: Introductionmentioning

confidence: 99%

Models for metal hydride particle shape, packing, and heat transfer

Smith

Fisher

2012

International Journal of Hydrogen Energy

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“…Therefore, internal heat transfer enhancements have become more attractive and can roughly divided in two ways: 1) Enhancement of the thermal conductivity of the metal hydride powder by insertion of aluminium foam [13][14][15], copper wire net structure [16] or by creating metal hydride compacts [17][18][19][20], 2) Integration of heat exchangers inside the bed such as embedded heat exchanger tubes [21][22][23], finned tube heat exchangers [24][25][26][27], spiral heat exchangers [28,29] or heat pipes [30].…”

Section: Introductionmentioning

confidence: 99%

Efficient hydrogen storage in up-scale metal hydride tanks as possible metal hydride compression agents equipped with aluminium extended surfaces

Gkanas

Grant

Khzouz

et al. 2016

International Journal of Hydrogen Energy

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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. AbstractIn the current work, a three-dimensional computational study regarding coupled heat and mass transfer during both the hydrogenation and dehydrogenation process in upscale cylindrical metal hydride reactors is presented, analysed and optimized. Three different heat management scenarios were examined at the degree to which they provide improved system performance. The three scenarios were: 1) Plain embedded cooling/heating tubes, 2) transverse finned tubes and 3) longitudinal finned tubes. A detailed optimization study was presented leading to the selection of the optimized geometries. In addition, two different types of hydrides, LaNi5 and an AB2-type intermetallic were studied as possible candidate materials for using as the first stage alloys in a two-stage metal hydride hydrogen compression system. As extracted from the above results, it is clear that the case of using a vessel equipped with 16 longitudinal finned tubes is the most efficient way to enhance the hydrogenation kinetics when using both LaNi5 and the AB2-alloy as the hydride agents. When using LaNi5 as the operating hydride the case of the vessel equipped with 60 embedded cooling tubes presents the same kinetic behaviour with the case of the vessel equipped with 12 longitudinal finned tubes, so in that way, by using extended surfaces to enhance the heat exchange can reduce the total number of tubes from 60 to 12. For the case of using the AB2-type material as the operating hydride the performance of the extended surfaces is more dominant and more effective comparing to the case of using the embedded tubes, especially for the case of the longitudinal extended surfaces.

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“…The dimensionless governing equations are shown in Table 4. Volume fraction of thermal promoter [-] Ca(NH 3 ) 2 Cl 2 + Graphite (Goetz and Marty, 1992) Ca(NH 3 ) 2 Cl 6 + Graphite (Goetz and Marty, 1992) MnCl 2 + Carbon (Spinner *) TiFe + Al (Buchner, 1982) LaNi 5 + Al (Ron and Josephy, 1988;Bershadsky et al, 1989) CaNi 5 Fig. 1 Improvement of effective thermal conductivities using additives.…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat Transfer Enhancement on Energy Release Rate from a Metal Hydride Tank

Nakaso

Shigenaga

Fukai

2007

J. Chem. Eng. Japan

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Metal hydride (MH) attracts considerable attention for not only hydrogen storage devices but also chemical heat pumps (CHPs). Many previous researchers pointed out low effective thermal conductivity of MH packed bed resulted in low performance. Indeed, several attempts have been done to improve it. However, no guideline for improving the thermal performance with heat transfer enhancement has been discussed. In this study, thermal performance for a packed bed reactor of MH is numerically investigated. Diagrams for the heat transfer enhancement are developed according to the numerical results. The previous strategies to improve effective thermal conductivity can be combined with the diagrams for the practical use.

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Permeability and thermal conductivity of porous metallic matrix hydride compacts

Cited by 39 publications

References 6 publications

Models for metal hydride particle shape, packing, and heat transfer

Models for metal hydride particle shape, packing, and heat transfer

Efficient hydrogen storage in up-scale metal hydride tanks as possible metal hydride compression agents equipped with aluminium extended surfaces

Effect of Heat Transfer Enhancement on Energy Release Rate from a Metal Hydride Tank

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