Volumetric displacement effects in Euler-Lagrange LES of particle-laden jet flows

Pakseresht, Pedram; Apte, Sourabh V.

doi:10.1016/j.ijmultiphaseflow.2018.12.013

Cited by 33 publications

(19 citation statements)

References 57 publications

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“…This effect, which is captured by the volume fraction factor in the continuity and momentum equations, is negligible in the semidilute regime. Pakseresht & Apte (2019) showed that effects due to volumetric displacement play a role when the particle volume fraction exceeds 5 %. In the present regime considered, the peaks of local particle volume fraction are of the order of , resulting in even within particle clusters.…”

Section: Governing Equationsmentioning

confidence: 99%

Accelerated decay of a Lamb–Oseen vortex tube laden with inertial particles in Eulerian–Lagrangian simulations

Shuai

Kasbaoui

2022

J. Fluid Mech.

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We investigate the effect of inertial particles on the stability and decay of a prototypical vortex tube, represented by a two-dimensional Lamb–Oseen vortex. In the absence of particles, the strong stability of this flow makes it resilient to perturbations, whereby vorticity and enstrophy decay at a slow rate controlled by viscosity. Using Eulerian–Lagrangian simulations, we show that the dispersion of semidilute inertial particles accelerates the decay of the vortex tube by orders of magnitude. In this work, mass loading is unity, ensuring that the fluid and particle phases are tightly coupled. Particle inertia and vortex strength are varied to yield Stokes numbers 0.1–0.4 and circulation Reynolds numbers 800–5000. Preferential concentration causes these inertial particles to be ejected from the vortex core forming a ring-shaped cluster and a void fraction bubble that expand outwards. The outward migration of the particles causes a flattening of the vorticity distribution, which enhances the decay of the vortex. The latter is further accelerated by small-scale clustering that causes enstrophy to grow, in contrast with the monotonic decay of enstrophy in single-phase two-dimensional vortices. These dynamics unfold on a time scale that is set by preferential concentration and is two orders of magnitude lower than the viscous time scale. Increasing particle inertia causes a faster decay of the vortex. This work shows that the injection of inertial particles could provide an effective strategy for the control and suppression of resilient vortex tubes.

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Section: Governing Equationsmentioning

confidence: 99%

Accelerated decay of a Lamb–Oseen vortex tube laden with inertial particles in Eulerian–Lagrangian simulations

Shuai

Kasbaoui

2022

J. Fluid Mech.

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“…The studied cases and the corresponding flow parameters are listed in Table 1. Detailed explanation and further results can be found in our recent work [30]. For each case, the results of standard and volumetric two-way couplings are compared together.…”

Section: Resultsmentioning

confidence: 99%

“…However, further downstream due to the jet spread and dispersion of particles, the local volume fraction of the carrier phase decreases so do the displacement effects. The increase in the prediction of volumetric coupling is attributed to the continuity source term, S v,cont , which drives the higher velocity in the regions with low volume fraction [30].…”

Section: Resultsmentioning

confidence: 99%

Modeling Drop Deformation Effects in the Euler-Lagrange Prediction of Liquid Jet in Cross Flow

Pakseresht¹,

Apte²

2020

Preprint

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Accurate prediction of spray atomization process using an Euler-Lagrange (EL) approach is challenging because of high volume fraction of the liquid phase in dense regimes. This would in reality displace a remarkable portion of the gaseous phase which is commonly ignored in the standard EL approaches. In addition, deformation of droplet due to the interaction of aerodynamic force, surface tension and viscous forces is typically neglected in modeling dense sprays. In this work, to capture the volumetric displacement effects using an EL approach, the spatio-temporal changes in the volume fraction of the gaseous phase are taken into account. This leads to zero-Mach number, variable density equations that give rise to a source term in both momentum and continuity equations. It is shown that the continuity source term increases the velocity and dynamics of the carrier phase close to the nozzle. However, owing to the jet spread and dispersion of droplets, these effects decrease further downstream. In order to quantify the droplet deformation effects, different models are compared together with an experimental data. Different breakup regimes are studied in order to identify the best model for each regime. The shape deformation effect is isolated by performing a single droplet injected into the cross flow with flow conditions similar to the bag-type breakup. A significant deviation in the motion of droplet is observed compared to a case where deformation is neglected.

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“…While Lagrangian-Eulerian spray models do converge, they are only conditionally convergent-the user must employ a surprisingly large number of computational parcels in order to observe convergence [40]. The Eulerian models also account for the volume occupied by the spray, which is typically neglected in Lagrangian-Eulerian simulations [33].…”

Section: Introductionmentioning

confidence: 99%

The Eulerian Lagrangian Mixing-Oriented (ELMO) Model

Schmidt¹,

Haghshenas²,

Mitra³

et al. 2021

Preprint

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Past Lagrangian/Eulerian modeling has served as a poor match for the mixinglimited physics present in many sprays. Though these Lagrangian/Eulerian methods are popular for their low cost, they are ill-suited for the physics of the dense spray core and suffer from limited predictive power. A new spray model, based on mixinglimited physics, has been constructed and implemented in a multi-dimensional CFD code. The spray model assumes local thermal and inertial equilibrium, with air entrainment being limited by the conical nature of the spray. The model experiences full two-way coupling of mass, momentum, species, and energy. An advantage of this approach is the use of relatively few modeling constants. The model is validated with three different sprays representing a range of conditions in diesel and gasoline engines.

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Volumetric displacement effects in Euler-Lagrange LES of particle-laden jet flows

Cited by 33 publications

References 57 publications

Accelerated decay of a Lamb–Oseen vortex tube laden with inertial particles in Eulerian–Lagrangian simulations

Accelerated decay of a Lamb–Oseen vortex tube laden with inertial particles in Eulerian–Lagrangian simulations

Modeling Drop Deformation Effects in the Euler-Lagrange Prediction of Liquid Jet in Cross Flow

The Eulerian Lagrangian Mixing-Oriented (ELMO) Model

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