The interaction of a shock with a dust deposit

Fletcher, B.

doi:10.1088/0022-3727/9/2/009

Cited by 44 publications

(13 citation statements)

References 3 publications

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“…Secondly, it has been established experimentally that shock and detonation waves propagated along dusty surfaces may cause particles to be entrained away from the near-wall region (Fletcher 1976;Merzkirch and Bracht 1978). In this situation, several possible mechanisms of dust rise, which predominate under different flow conditions, were discussed (Gerrard 1963;Bracht and Merzkirch 1979;Hishida and Hayashi 1989).…”

Section: The Saffman Force In Aerosol Flowsmentioning

confidence: 99%

Aerosol flow through a long micro-capillary: collimated aerosol beam

Akhatov

Hoey

Swenson

2007

Microfluid Nanofluid

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A micro-capillary system capable of generating a focused collimated aerosol beam (CAB) is demonstrated both theoretically and experimentally. The approach is based on a manifestation of the Saffman force where high velocity (*100 m/s) aerosol particles, flowing through a micro-capillary (d * 100 lm and l * 1 cm), migrate perpendicular to the centerline of the capillary. Upon exiting the micro-capillary system, the particles maintain momentum, and when the aerosol is comprised of solid-inliquid dispersions such as Ag nanoparticle ink, the CAB approach enables printing of advanced materials features with linewidth B 10 lm.

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Section: The Saffman Force In Aerosol Flowsmentioning

confidence: 99%

Aerosol flow through a long micro-capillary: collimated aerosol beam

Akhatov

Hoey

Swenson

2007

Microfluid Nanofluid

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“…Fletcher investigated the claims of Gerrard and concluded through experimentats and theoretical analysis that the primary mechanism of dust lifting is the rapid flow behind the propagating shock across the surface of the dust, instead of shock wave propagation through the dust layer as suggested by Gerrard (Fletcher, 1963). Bracht and Merzkirch identified the governing force in dust lifting is the Saffman force and supported their experimental work with a numerical model (Merzkirch & Bracht, 1978).…”

Section: Experimental Studiesmentioning

confidence: 92%

A New Facility for Studying Shock-Wave Passage Over Dust Layers

Marks

Chowdhury

Petersen

et al. 2015

29th International Symposium on Shock Waves 2

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To ensure safety regarding dust explosion hazards, it is important to study the dust lifting process experimentally and identify important parameters that will be valuable for development and validation of numerical predictions of this phenomenon. A new shock tube test section was developed and integrated into an existing shock tube facility. The test section allows for shadowgraph or laser scattering techniques to track dust layer particle motion. The test section is designed to handle an initial pressure of 1 atm with an incident shock wave velocity up to Mach 2 to mimic real world conditions. The test section features an easily removable dust pan and inserts to allow for adjustment of dust layer thickness. The design allows for the changing of experimental variables including initial pressure, Mach number, dust layer thickness and characteristics of the dust itself. A separate vacuum manifold was designed to protect existing equipment from negative side effects of the dust. A study was performed to demonstrate the capabilities of the new facility and to compare results with experimental trends formerly established in the literature. Fourty-micron limestone dust with a layer thickness of 3.2 mm was subjected to Mach 1.22 and 1.38 shock waves, and a high-speed shadowgraph was used for flow visualization. Dust layer rise height was graphed with respect to shock wave propagation.Dust particles subjected to a Mach 1.38 shock wave rose more rapidly and to a greater height with respect to shock wave propagation than particles subjected to a Mach 1.22 shock wave. These results are in agreement with trends found in the literature, and a new area of investigation was identified.iii ACKNOWLEDGEMENTS

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“…Former experimental works have studied the interaction of unsteady dust layers with different elements of gas-dynamic flows (e.g., shock, compression, and expansion waves). Earlier shock and dust particle interaction experiments focused on understanding the phenomenon of dust lifting [3][4][5][6][7][8][9][10][11]. For example, Fletcher's [5] explanation of the mechanism of dust lifting was based on experiments as well as theoretical analysis.…”

Section: Introductionmentioning

confidence: 99%

“…Earlier shock and dust particle interaction experiments focused on understanding the phenomenon of dust lifting [3][4][5][6][7][8][9][10][11]. For example, Fletcher's [5] explanation of the mechanism of dust lifting was based on experiments as well as theoretical analysis. He criticized Gerrard's [4] conclusion that dust entrainment is under the action of a shock wave passing through the dust layer.…”

Section: Introductionmentioning

confidence: 99%

A new facility for studying shock-wave passage over dust layers

et al. 2015

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Dust explosion hazards in areas where coal and other flammable materials are found have caused unnecessary loss of life and halted business operations in some instances. The elimination of secondary dust explosion hazards, i.e. reducing dust dispersion, can be characterized in shock tubes to understand shock-dust interactions. For this reason, a new shock-tube test section was developed and integrated into an existing shock-tube facility. The test section has large windows to allow for the use of the shadowgraph technique to track dust-layer growth behind a passing normal shock wave, and it is designed to handle an initial pressure of 1 atm with an incident shock wave Mach number as high as 2 to mimic real-world conditions. The test section features an easily removable dust pan with inserts to allow for adjustment of the dust-layer thickness. The design also allows for changing the experimental variables such as initial pressure, shock Mach number (M s ), dust-layer thickness, and the characteristics of the dust itself. The characterization experiments presented herein demonstrate the advantages of the authors' test techniques toward providing new physical insights over a wider range of data than what have been available heretofore in the literature. Limestone dust with a layer thickness of 3.2 mm was subjected to M s = 1.23, 1.32, and 1.6 shock waves, and dust-layer rise height was mapped with respect to time after shock passage. Dust particles subjected to a M s = 1.6 shock wave rose more rapidly and to a greater Communicated by C-Y.height with respect to shock wave propagation than particles subjected to M s = 1.23 and 1.32 shock waves. Although these results are in general agreement with the literature, the new data also highlight physical trends for dust-layer growth that have not been recorded previously, to the best of the authors' knowledge. For example, the dust-layer height rises linearly until a certain time where the growth rate is dramatically reduced, and in this second regime there is clear evidence of surface vertical structures at the dust-air interface.

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The interaction of a shock with a dust deposit

Cited by 44 publications

References 3 publications

Aerosol flow through a long micro-capillary: collimated aerosol beam

Aerosol flow through a long micro-capillary: collimated aerosol beam

A New Facility for Studying Shock-Wave Passage Over Dust Layers

A new facility for studying shock-wave passage over dust layers

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