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Structure and control of a particle-...

Longmire, Ellen Kathryn.

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Structure and control of a particle-laden jet.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Structure and control of a particle-laden jet./
Author:	Longmire, Ellen Kathryn.
Description:	243 p.
Notes:	Source: Dissertation Abstracts International, Volume: 52-01, Section: B, page: 0479.
Contained By:	Dissertation Abstracts International52-01B.
Subject:	Engineering, Mechanical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9115810

Structure and control of a particle-laden jet.
Longmire, Ellen Kathryn.

Structure and control of a particle-laden jet. - 243 p.

Source: Dissertation Abstracts International, Volume: 52-01, Section: B, page: 0479.

Thesis (Ph.D.)--Stanford University, 1991.

The interaction of solid particles with the temporal features of a turbulent flow has direct relevance to problems such as particle and spray combustion and the processing of particulate solids. The objective of the present study was to examine the behavior of particles in a jet dominated by vortex ring structures. An axisymmetric air jet laden with 55 micron glass particles was forced axially with an acoustic speaker to organize the vortex ring structures rolling up in the free shear layer downstream of the nozzle exit. Visualization studies of forced and unforced flow with Reynolds number on the order of 20000 were completed using a pulsed copper vapor laser. Instantaneous photographs and videotapes of strobed forced flow show that particles are clustered in the saddle regions downstream of the vortex rings and propelled away from the jet axis by the outwardly moving flow in these regions. Phase-averaged spatial distributions of particle number density computed from digitized photographs and phase-averaged particle velocity measurements yield further evidence that particle dispersion is governed not by diffusion but by convection due to large-scale turbulence structures. Dispersion control mechanisms were demonstrated using single and double frequency waveforms input to the speaker for particle-to-air mass loading ratios of up to 1.0.Subjects--Topical Terms:

783786
Engineering, Mechanical.

Structure and control of a particle-laden jet.
LDR:02934nmm 2200277 4500 001 1830196
005 20070423125521.5
008 130610s1991 eng d
035 $a (UnM)AAI9115810
035 $a AAI9115810
040 $a UnM $c UnM
100 1 $a Longmire, Ellen Kathryn. $3 1919036
245 1 0 $a Structure and control of a particle-laden jet.
300 $a 243 p.
500 $a Source: Dissertation Abstracts International, Volume: 52-01, Section: B, page: 0479.
500 $a Adviser: John K. Easton.
502 $a Thesis (Ph.D.)--Stanford University, 1991.
520 $a The interaction of solid particles with the temporal features of a turbulent flow has direct relevance to problems such as particle and spray combustion and the processing of particulate solids. The objective of the present study was to examine the behavior of particles in a jet dominated by vortex ring structures. An axisymmetric air jet laden with 55 micron glass particles was forced axially with an acoustic speaker to organize the vortex ring structures rolling up in the free shear layer downstream of the nozzle exit. Visualization studies of forced and unforced flow with Reynolds number on the order of 20000 were completed using a pulsed copper vapor laser. Instantaneous photographs and videotapes of strobed forced flow show that particles are clustered in the saddle regions downstream of the vortex rings and propelled away from the jet axis by the outwardly moving flow in these regions. Phase-averaged spatial distributions of particle number density computed from digitized photographs and phase-averaged particle velocity measurements yield further evidence that particle dispersion is governed not by diffusion but by convection due to large-scale turbulence structures. Dispersion control mechanisms were demonstrated using single and double frequency waveforms input to the speaker for particle-to-air mass loading ratios of up to 1.0.
520 $a In a separate set of experiments, crown-shaped nozzle attachments were used to disturb the axisymmetry of the vortex rings. Time-averaged views of the unforced flow showed significant deviations of the jet from axisymmetry. Phase-averaged views of forced flow revealed strong variations in entrainment along different azimuthal planes and repeatable longitudinal vortex structures attached to the larger-scale vortex rings. When tooth length and number on the nozzle attachments were varied, the stability and propagation patterns of the longitudinal structures could be altered. Although these secondary structures strongly affected jet fluid mixing, they were too small to have more than a weak effect on particle dispersion patterns.
590 $a School code: 0212.
650 4 $a Engineering, Mechanical. $3 783786
650 4 $a Physics, Fluid and Plasma. $3 1018402
690 $a 0548
690 $a 0759
710 2 0 $a Stanford University. $3 754827
773 0 $t Dissertation Abstracts International $g 52-01B.
790 1 0 $a Easton, John K., $e advisor
790 $a 0212
791 $a Ph.D.
792 $a 1991
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9115810