Fragmentation of highly porous char particles burning in regime I

Zhang, X.; Dukhan, A.; Kantorovich, I.I.; Bar‐Ziv, Ezra

doi:10.1016/0010-2180(96)00045-4

Cited by 12 publications

(6 citation statements)

References 10 publications

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“…Assuming 100 m pores, emissivity and refractive index to be approximately 1, and a maximum temperature of 450 K, it is k R 0:002 W m ÿ1 K ÿ1 . This is low compared to the other conductivities and we neglect conduction by thermal radiation transport [2,17]. The density of the dust bed is b 0:45 g cm ÿ3 and the heat capacity is c b 712 W Kg ÿ1 K ÿ1 .…”

mentioning

confidence: 99%

Dust Eruptions by Photophoresis and Solid State Greenhouse Effects

Wurm

Krauß

2006

Phys. Rev. Lett.

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We carried out experiments that show a gas pressure dependent ability of light to eject particles from a dust bed. Dust eruptions also occur upon removal of the light source. This can be attributed to a solid state greenhouse effect and photophoretic forces. This ejection mechanism works at light intensities larger than 6 kW/m2 but in extreme cases might work as low as 1 kW/m2. It can be applied to sunlit dust on Mars where it aids or triggers dust lift-off from the surface into the atmosphere. It is of importance for dusty bodies at the inner edge of protoplanetary disks where it leads to light induced erosion. The effect also offers a base for technical applications of dust removal in low pressure environments.

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confidence: 99%

Dust Eruptions by Photophoresis and Solid State Greenhouse Effects

Wurm

Krauß

2006

Phys. Rev. Lett.

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“…These can lead to both p-and n-type semiconducting behavior of carbons and thus make possible the fabrication of inter-and intramolecular logic gates, the "basic units of computers" [81]. More recently, Bar-Ziv and co-workers [82,83] explored the relationship between carbon porosity, its percolation threshold, and thermal conductivity.…”

Section: Bulk Propertiesmentioning

confidence: 99%

“…Gasification-induced carbon densification (e.g., particle shrinkage) is another intriguing experimental fact [82,83,[299][300][301][302][303][304][305][306][307]. Like annealing, it is a consequence of structural ordering, but here thermally induced diffusion is assisted by chemical removal of the more reactive carbon atoms.…”

Section: Solid Phasementioning

confidence: 99%

Physicochemical Properties of Carbon Materials: A Brief Overview

Radović

2008

Carbon Materials for Catalysis

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“…Since the PPF is generated due to non-uniform radiation on a particle surface, the dominance of radiative heat transfer implies that the PPF is important under these conditions. Furthermore, measurement of the PPF is an effective way to measure the thermal conductivity of a sub-millimetre particle providing information on that particle's internal structures [15,16]. In the size range of interest for combustion, theoretical investigations on the PPF were performed by Yalamov et al [17], Pluchino [18] and Mackowski [19].…”

Section: Introductionmentioning

confidence: 99%

“…A method to uncouple these forces was developed by Weiss et al [15] and Dukhan et al [16]. The uncoupling procedure was based on calculating the FCF and subtracting it from the sum.…”

Section: Introductionmentioning

confidence: 99%

Direct determination of 3D forces applied on a particle suspended in an electrodynamic chamber

Zhang

Bar‐Ziv

1996

Meas. Sci. Technol.

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The main motivation of the present work is to enable one to carry out a direct quantitative measurement of 3D force balance applied on a suspended particle in an electrodynamic chamber (EDC). For this, the absolute values of electric field parameters are essential. Both horizontal and vertical electric field components were analysed theoretically and experimentally. From the theoretical analysis of the motion of a charged particle in an EDC, two relationships relating motion parameters to electric field strength were found. These relationships were validated experimentally from measurements of 17 polystyrene and char particles with various densities and sizes. Consequently, the absolute 3D field parameters were determined. This method was used to determine the absolute value of the photophoretic force (PPF) and the free convection force (FCF) applied on a suspended particle. In these experiments, the particle was irradiated horizontally by a focused laser beam. Consequently, the PPF was developed horizontally whereas the FCF was developed vertically. The present measurement indicated that the PPF is much smaller than the FCF, in contrast to previous reports.

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Fragmentation of highly porous char particles burning in regime I

Cited by 12 publications

References 10 publications

Dust Eruptions by Photophoresis and Solid State Greenhouse Effects

Dust Eruptions by Photophoresis and Solid State Greenhouse Effects

Physicochemical Properties of Carbon Materials: A Brief Overview

Direct determination of 3D forces applied on a particle suspended in an electrodynamic chamber

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