Future Research Needs in Convective Heat and Mass Transport in Porous Media

Georgiadis, John G.

doi:10.1007/978-94-011-3220-6_39

Cited by 4 publications

(2 citation statements)

References 27 publications

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“…Until recently, there have been no effective PMC visualization techniques which determine the convection pattern non-invasively. The current lack of and need for visualization and local velocity information has been pointed out in recent reviews by Torrance et al (1982) and by Georgiadis (1991). Much of the existing experimental data are limited to heat transfer measurements (Schneider 1963;Katto & Masuoka 1967;Combarnous 1970;Buretta & Berman 1976;Kaneko, Mohtadi & Aziz 1974;Yen 1974), and these data are often inconsistent with each other, a fact which the present studies, and related work (Howle, Behringer & Georgiadis 1997) may explain.…”

Section: Introductionmentioning

confidence: 62%

Convection and flow in porous media. Part 1. Visualization by magnetic resonance imaging

et al. 1997

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We describe an experimental study of porous media convection (PMC) from onset to 8Ra c . The goal of this work is to provide non-invasive imaging and high-precision heat transport measurements to test theories of convection in PMC. We obtain velocity information and visualize the convection patterns using magnetic resonance imaging (MRI). We study both ordered and disordered packings of mono-disperse spheres of diameter d = 3.204 ± 0.029 mm, in circular, rectangular, and hexagonal planforms. In general, the structure of the medium plays a role which is not predicted by theories which assume a homogeneous system. Disordered media are prepared by pouring mono-disperse spheres into the container. Large ordered regions of close packing for the spheres, with grain boundaries and isolated defects, characterize these media. The defects and grain boundaries play an important role in pattern formation in disordered media. Any deviation from close packing produces a region of larger porosity, hence locally larger permeability. The result is spatial variations in the Rayleigh number, Ra. We define the critical Ra, Ra c , as the Rayleigh number at the onset of convection in the ordered regions. We find that stable localized convective regions exist around grain boundaries and defects at Ra < Ra c . These remain as pinning sites for the convection patterns in the ordered regions as Ra increases above Ra c up to 5Ra c , the highest Ra studied in the disordered media. In ordered media, spheres are packed such that the only deviations from close packing occur within a thin (

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Section: Introductionmentioning

confidence: 62%

Convection and flow in porous media. Part 1. Visualization by magnetic resonance imaging

et al. 1997

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“…Heat and mass transfer coefficients should be measured particularly for equiaxed crystals and columnar dendrite tips. Promising experimental methods include the use of transparent model alloys and optical diagnostic techniques (McCay et al, 1991) and Magnetic Resonance Imaging (Georgiadis, 1991). It should be noted that measurements at single dendrite tips [see Glicksman et al (1986)] would not be directly useful, because of interference of the thermal and solutal fields from adjacent crystals and because the averaging volume contains several crystals.…”

Section: Interfacial Dragmentioning

confidence: 99%

Mathematical Modeling of Transport Phenomena During Alloy Solidification

Beckermann

Viskanta

1993

Applied Mechanics Reviews

207

114

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Mathematical modeling of mass, momentum, heat, and species transport phenomena occurring during solidification of metal alloys is reviewed. Emphasis is placed on the incorporation of the effects of the solid structure and the interactions between the solid and liquid phases on a microscopic scale into a (macroscopic) model of the transport phenomena occurring at the system scale. Both columnar and equiaxed growth structures, as well as laminar convection of liquid and solid crystals are considered. The macroscopic conservation equations are introduced via a volume averaging approach and commonly made simplifications are examined. Basic constitutive relations for the phase interactions occurring in alloy solidification are presented. Recent progress in including nucleation, microsegregation, undercooling and other microscopic phenomena in the macroscopic equations is reviewed. The specific areas where future theoretical and experimental research is needed are identified.

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A comparison of numerical models for evaporative two-phase flow in a self-heated porous medium

Kim

1996

Computers & Fluids

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Future Research Needs in Convective Heat and Mass Transport in Porous Media

Cited by 4 publications

References 27 publications

Convection and flow in porous media. Part 1. Visualization by magnetic resonance imaging

Convection and flow in porous media. Part 1. Visualization by magnetic resonance imaging

Mathematical Modeling of Transport Phenomena During Alloy Solidification

A comparison of numerical models for evaporative two-phase flow in a self-heated porous medium

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