Turbulent transport of particles in a straight square duct

Sharma, Gaurav; Phares, Denis J.

doi:10.1016/j.ijmultiphaseflow.2006.02.010

Cited by 45 publications

(39 citation statements)

References 21 publications

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“…The data point corresponding to the smallest value of particle inertia (τ + p = 1) is slightly below the data envelope, suggesting that deposition is less likely in a square duct for low-inertia particles than in a circular duct. This is consistent with a previous observation that low-inertia particles are more likely than high-inertia particles to be carried back into the core of the square duct by the mean secondary swirling flow (Sharma and Phares 2006). By contrast, higher inertia particles are efficiently carried to the walls where they are more likely to deposit or accumulate near the wall in regions of high strain rate.…”

Section: Deposition Ratesupporting

confidence: 92%

“…This suggests a preferential enhancement of deposition of higher-inertia particles by the secondary flows unique to the square duct, or a suppression of deposition of the lower-inertia particles by the secondary flows, or perhaps both. Deposition suppression of particles having τ + p ≤ 15 is not immediately obvious from Figure 3, but is consistent with the observation by Sharma and Phares (2006) that lower-inertia particles are increasingly more likely to be carried back to the center of the duct by the mean swirling flows. Sharma and Phares (2006) noted that centrifuging by the mean swirl is not a valid explanation for this phenomenon, since the Stokes number based on the mean off-axis velocity and the size of the mean circulation is much smaller than unity for all values FIG.…”

Section: Deposition Patternssupporting

confidence: 88%

“…The numerical solution of the Navier-Stokes equations and subsequent flow verification have been detailed in the previous study (Sharma and Phares 2006), so only the main points are summarized here. The straight square duct, shown in Figure 1, is bounded by no-slip walls in the cross-stream directions and the flow is assumed to be periodic in the streamwise direction.…”

Section: Flow Simulationmentioning

confidence: 99%

“…The first, an LES study reported by Winkler et al (2004), focuses on the preferential concentration of finite-inertia particles, especially near the walls of the duct. The second, a DNS study recently reported by the authors of this study (Sharma and Phares 2006), focuses on longitudinal and lateral single particle-and pair-dispersion statistics. That study demonstrated that the secondary flows act in combination with turbophoresis to transport particles between the duct core and the walls.…”

Section: Introductionmentioning

confidence: 99%

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A DNS Study of Aerosol Deposition in a Turbulent Square Duct Flow

Phares

Sharma

2006

Aerosol Science and Technology

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A particle-laden turbulent flow through a square duct was simulated using a direct numerical solution of the Navier-Stokes equations coupled with Langrangian particle tracking. Computations of particle transport were employed to elucidate the mechanisms by which particles with varying inertia deposit to the walls of a square duct. Gravity was neglected and a one-way coupling was assumed between the particles and the fluid. The computational results demonstrate that, although the aerosol penetration through a square duct is not significantly different than through a circular pipe, there exist differences in the transport and deposition mechanisms. Most notably, the off-axis secondary flows unique to the square duct preferentially deposit higher-inertia particles closer to the corners of the duct. By contrast, the same secondary flows act to suppress the deposition of lower-inertia particles to the duct corners by efficiently transporting them back towards the duct core before deposition can occur.

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Section: Deposition Ratesupporting

confidence: 92%

Section: Deposition Patternssupporting

confidence: 88%

Section: Flow Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A DNS Study of Aerosol Deposition in a Turbulent Square Duct Flow

Phares

Sharma

2006

Aerosol Science and Technology

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“…% 300 Gavrilakis (1992), Joung et al (2007), Pinelli et al (2010) and Xu (2009) Madabhushi and Vanka (1991) and Xu and Pollard (2001) Heat transfer by Piller and Nobile (2002) and Ma et al (2007) Heat transfer by Pallares and Davidson (2002) and Vázquez and Métais (2002) Rotating duct by Yang et al (2010) Rotating duct by Pallares and Davidson (2000) With particles by Sharma and Phares (2006) and Zhang et al (2011Zhang et al ( , 2014Zhang et al ( , 2015 With particles by Winkler et al (2004) and Winkler and Rani (2009) …”

Section: Dns Les Ransmentioning

confidence: 99%

Direct numerical simulation of a fully developed turbulent square duct flow up to Reτ=1200

Zhang

Trias

Gorobets

et al. 2015

International Journal of Heat and Fluid Flow

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a b s t r a c tVarious fundamental studies based on a turbulent duct flow have gained popularity including heat transfer, magnetohydrodynamics as well as particle-laden transportation. An accurate prediction on the turbulent flow field is critical for these researches. However, the database of the mean flow and turbulence statistics is fairly insufficient due to the enormous cost of numerical simulation at high Reynolds number. This paper aims at providing available information by conducting several Direct Numerical Simulations (DNS) on turbulent duct flows at Re s ¼ 300; 600; 900 and 1200. A quantitative comparison between current and previous DNS results was performed where a good agreement was achieved at Re s ¼ 300. However, further comparisons of the present results with the previous DNS results at Re s ¼ 600 obtained with much coarser meshes revealed some discrepancies which can be explained by the insufficient mesh resolution. At last, the mean flow and turbulent statistics at higher Re s was presented and the effect of Re s on the mean flow and flow dynamics was discussed.

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Mechanisms of particle dispersion in a turbulent, square duct flow

Fairweather¹,

Ye²

2009

AIChE Journal

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Particle dispersion in a square duct flow is studied using large eddy simulation combined with Lagrangian particle tracking under conditions of one-way coupling. The flow has a bulk Re ¼ 250 k, with six particle sizes ranging from 5 to 1000 lm. Results obtained for the fluid phase show good agreement with experimental data. For particles, predictions demonstrate that secondary flows within the duct dominate small particle dispersion and result in a uniform distribution, whereas gravity promotes the deposition of large particles on the duct floor. For the largest particles, the secondary flows contribute to particle concentration in corners on the duct floor, with these particles also clustering in low-velocity regions close to the floor. A detailed analysis of the influence of the flow on particle distribution is provided through consideration of the particle dispersion function, with the mechanisms of particle dispersion elucidated using a dynamical analysis.

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Turbulent transport of particles in a straight square duct

Cited by 45 publications

References 21 publications

A DNS Study of Aerosol Deposition in a Turbulent Square Duct Flow

A DNS Study of Aerosol Deposition in a Turbulent Square Duct Flow

Direct numerical simulation of a fully developed turbulent square duct flow up to Reτ=1200

Mechanisms of particle dispersion in a turbulent, square duct flow

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