One-dimensional particle velocity probability densities measured in turbulent gas-particle duct flow

Carlson, C.; Peskin, Richard L.

doi:10.1016/0301-9322(75)90029-4

Cited by 17 publications

(8 citation statements)

References 5 publications

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“…Their results also confirmed several previous investigations which find a larger streamwise velocity component variance for particles relative to the corresponding fluid intensity in inhomogeneous flows (e.g. Soo, Ihrig & El Kouh 1960;Carlson & Peskin 1975;Tsuji & Morikawa 1982;Steimke & Dukler 1983;Rogers & Eaton 1990). This phenomenon has been predicted theoretically in the presence of a constant mean velocity gradient by Liljegren (1993).…”

Section: Introductionsupporting

confidence: 90%

Direct numerical simulation of a confined three-dimensional gas mixing layer with one evaporating hydrocarbon-droplet-laden stream

Miller¹,

1999

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Direct numerical simulations are performed of a confined three-dimensional, temporally developing, initially isothermal gas mixing layer with one stream laden with as many as 7.3×10 5 evaporating hydrocarbon droplets, at moderate gas temperature and subsonic Mach number. Complete two-way phase couplings of mass, momentum and energy are incorporated which are based on a thermodynamically self-consistent specification of the vapour enthalpy, internal energy and latent heat of vaporization. Effects of the initial liquid mass loading ratio (ML), initial Stokes number (St 0 ), initial droplet temperature and flow three-dimensionality on the mixing layer growth and development are discussed. The dominant parameter governing flow modulation is found to be the liquid mass loading ratio. Variations in the initial Stokes number over the range 0.5 6 St 0 6 2.0 do not cause significant modulations of either first-or second-order gas phase statistics. The mixing layer growth rate and kinetic energy are increasingly attenuated for increasing liquid loadings in the range 0 6 ML 6 0.35. The laden stream becomes saturated before evaporation is completed for all but the smallest liquid loadings owing to: (i) latent heat effects which reduce the gas temperature, and (ii) build up of the evaporated vapour mass fraction. However, droplets continue to be entrained into the layer where they evaporate owing to contact with the relatively higher-temperature vapour-free gas stream. The droplets within the layer are observed to be centrifuged out of high-vorticity regions and to migrate towards high-strain regions of the flow. This results in the formation of concentration streaks in spanwise braid regions which are wrapped around the periphery of secondary streamwise vortices. Persistent regions of positive and negative slip velocity and slip temperature are identified. The velocity component variances in both the streamwise and spanwise directions are found to be larger for the droplets than for the gas phase on the unladen stream side of the layer; however, the cross-stream velocity and temperature variances are larger for the gas. Finally, both the mean streamwise gas velocity and droplet number density profiles are observed to coincide for all ML when the cross-stream coordinate is normalized by the instantaneous vorticity thickness; however, first-order thermodynamic profiles do not coincide.

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Section: Introductionsupporting

confidence: 90%

Direct numerical simulation of a confined three-dimensional gas mixing layer with one evaporating hydrocarbon-droplet-laden stream

Miller¹,

1999

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“…Normalization by the fluid centerline velocity would not affect this value by more than 10%, which would still result in particle intensities which are large compared with those measured in homogeneous turbulence. Enhancement of the particle intensity has been observed by Soo et al (1960), Carlson and Peskin (1975) and Steimke and Dukler (1983) and Tsuji and Morikawa (1982). The explanation provided by the these investigators varies; Soo et al suggest that the enhancement is due to the influence of gravity on the flow field.…”

Section: Enhanced Particle Velocity Intensitiesmentioning

confidence: 85%

“…This does not occur in many cases of physical significance, particularly in internal flows when the particle response parameter is large. Significant velocity slip between large particles and air has been observed by Steimke and Dukler (1983), Carlson and Peskin (1975), Tsuji and Morikawa (1982), Tsuji et al (1984), and Lee and Durst (1982). Thus the prediction that large particles stabilize the flow may not be applicable to internal flows of suspensions carrying extremely large particles.…”

Section: Dimensionsless Parameters Describing Influence On Turbulencementioning

confidence: 96%

“…Velocitysize correlations may be calculated from this information and used to determine the degree to which the variation in the size of the particle phase contributes to the measured particle velocity variance. The importance of the particle size variation on the particle velocity characteristics was discussed by Carlson and Peskin (1975).…”

Section: Introductionmentioning

confidence: 99%

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Laser velocimetry measurements in a horizontal gas-solid pipe flow

Liljegren

Vlachos

1990

Experiments in Fluids

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This paper presents laser measurements of particle velocities in a horizontal turbulent two-phase pipe flow. A phase Doppler particle analyzer, (PDPA), was used to obtain particle size, velocity, and rms values of velocity fluctuations. The particulate phase consisted of glass spheres 50 Ixm in diameter with the volume fraction of the suspension in the range q~p= 10 -4 to 4~p= 10 -3. The results show that the turbulence increases with particle loading.

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“…Laser-Doppler velocimetry (LDV) may be used as an indirect method of measuring gas velocities in a variety of two-phase flows (Durst and Zare 1975), including dustygas flows (Carlson and Peskin 1975;Modarress et al 1984), provided that the particle concentration is not overly large as to prevent optical access to the flow field. In such flows the seed particles occur naturally as the particulate phase, but the LDV is not employed in the conventional manner; the particles, rather than existing solely as a means to obtain the gas velocity, are an intrinsic part of the flow field and may be too large to meet the criterion of accurately tracking the gas motion.…”

Section: Introductionmentioning

confidence: 99%

On the method of indirectly measuring gas and particulate phase velocities in shock induced dusty-gas flows

Lock

1993

Experiments in Fluids

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A method of indirectly measuring the temporally varying velocities of the gas and particulate phases in the nonequilibrium region of a shock wave moving at constant speed in a dusty-gas flow is described, and this method is assessed by using experimental data from shock-induced air flows containing 40 pm diameter glass beads in a dusty-gas shock-tube facility featuring a large horizontal channel (19.7-cm by 7.6-cm in cross-section). Simultaneous measurements of the shock-front speed with time-of-arrival gauges, particle concentration by light extinctiometry and gas-particle mixture density by beta-ray absorption are used in conjunction with two mass conservation laws to obtain the indirect velocity measurements of both phases. A second indirect measurement of the gas-phase velocity is obtained when the gas pressure is simultaneously recorded along with the particle concentration and shock-front speed when used in conjunction with the conservation of mixture momentum. Direct measurements of the particulate-phase velocity by laserDoppler velocimetry are also presented, as a means of assessing the indirect velocity measurement method.

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One-dimensional particle velocity probability densities measured in turbulent gas-particle duct flow

Cited by 17 publications

References 5 publications

Direct numerical simulation of a confined three-dimensional gas mixing layer with one evaporating hydrocarbon-droplet-laden stream

Direct numerical simulation of a confined three-dimensional gas mixing layer with one evaporating hydrocarbon-droplet-laden stream

Laser velocimetry measurements in a horizontal gas-solid pipe flow

On the method of indirectly measuring gas and particulate phase velocities in shock induced dusty-gas flows

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