Analysis of non‐Brownian particle deposition from turbulent liquid‐flow

Abstract

International audienceThe deposition of non-Brownian particles from turbulent liquid-flow onto channel walls is numerically analyzed. Theapproach combines Lagrangian particle tracking with a kinematic model of the near-wall shear layer. For nonbuoyantparticles, direct interception is the main deposition mechanism and the deposition velocity scales as the particle diameter(in wall units) to the power of 1.7. When wall/particle hydrodynamic interactions are taken into account, the depositionvelocity is significantly reduced and the correction factor scales as the cubic root of the wall roughness to particlediameter ratio. For buoyant particles, sedimentation is usually the predominant deposition mechanism and the hydrodynamicinteractions significantly affect the deposition velocity when the drainage characteristic time driven by buoyancyis of the order of the particle residence time close to the wall. Last, a wall-function for the suspended particles is proposed

Large-eddy simulation of turbulent dispersed flows: a review of modelling approaches

“…In addition, because sweeps and ejections are mainly responsible for particle motion to and away from the wall, only the flow pattern in the cross-flow plane is modelled. In spite of its simplicity, the model predictions in terms of deposition velocity (the only observable investigated by the authors) at varying particle-to-liquid density ratio, particle diameter, friction velocity and wall roughness for the specific case of hydrosol particles are in good agreement with the experimental results [28]. Other models that could be employed as wall-layer functions could be the stochastic models of Guingo and Minier [50] and Jin et al [57], developed specifically to predict particle transport and deposition in turbulent boundary layers.…”

“…To the best of this author's knowledge, no wall-layer model has been yet developed and coupled to LES to simulate particle-laden turbulent flows. In the recent study of Dupuy et al [28], however, a candidate model has been tested (but not yet in combination with DNS) to compute the deposition of non-Brownian particles in turbulent open channel flow. The model is based on the formulation proposed by Fan and Ahmadi [29] to estimate the deposition rate of spherical particles from turbulent air streams in vertical ducts.…”

Toward Better Control of Inclusion Cleanliness in a Gas Stirred Ladle Using Multiscale Numerical Modeling

“…Particular attention has been paid to inclusion entrapment at the liquid metal/slag interface. It is modeled following the approach based on a turbulent deposition law developed initially by Wood [ 27 ] for aerosols and adapted to hydrosols by Xayasenh [ 28 ]. The entrapment of inclusions at the ladle walls is not considered yet but has been found to be negligible [ 29 ].…”

Large eddy simulation of inertial fiber deposition mechanisms in a vertical downward turbulent channel flow

“…can be constructed in which three distinct deposition regimes are present 5,8,9 . In regime 1, sub-micron particle ( deposit as a consequence of turbulent diffusion and impaction due to the growing particle inertia.…”