Surface-resolved dynamic simulation of charged non-spherical particles

Ruan, Xuan; Gorman, Matthew T.; Li, Shuiqing; Ni, Rui

doi:10.1016/j.jcp.2022.111381

Cited by 7 publications

(3 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this dilute system, the average separation between charged particles is large compared with the particle size (), indicating an insignificant effect of particle polarization (Ruan et al. 2022). Therefore, the electrostatic force acting on each particle can be obtained by summing the pairwise Coulomb force from other particles , which reads Here, is the vacuum permittivity, is the point charge located at the centroid of particle .…”

Section: Methodsmentioning

confidence: 99%

Effects of electrostatic interaction on clustering and collision of bidispersed inertial particles in homogeneous and isotropic turbulence

Ruan,

Gorman,

2024

J. Fluid Mech.

Self Cite

View full text Add to dashboard Cite

In sandstorms and thunderclouds, turbulence-induced collisions between solid particles and ice crystals lead to inevitable triboelectrification. The charge segregation is usually size dependent, with small particles charged negatively and large particles charged positively. In this work, we perform numerical simulations to study the influence of charge segregation on the dynamics of bidispersed inertial particles in turbulence. Direct numerical simulations of homogeneous isotropic turbulence are performed with the Taylor Reynolds number ${Re}_{\lambda }=147.5$ , while particles are subjected to both electrostatic interactions and fluid drag, with Stokes numbers of 1 and 10 for small and large particles, respectively. Coulomb repulsion/attraction is shown to effectively inhibit/enhance particle clustering within a short range. Besides, the mean relative velocity between same-size particles is found to rise as the particle charge increases because of the exclusion of low-velocity pairs, while the relative velocity between different-size particles is almost unaffected, emphasizing the dominant roles of differential inertia. The mean Coulomb-turbulence parameter, ${Ct}_0$ , is then defined to characterize the competition between the Coulomb potential energy and the mean relative kinetic energy. In addition, a model is proposed to quantify the rate at which charged particles approach each other and to capture the transition of the particle relative motion from the turbulence-dominated regime to the electrostatic-dominated regime. Finally, the probability distribution function of the approach rate between particle pairs is examined, and its dependence on the Coulomb force is further discussed using the extended Coulomb-turbulence parameter.

show abstract

Section: Methodsmentioning

confidence: 99%

Effects of electrostatic interaction on clustering and collision of bidispersed inertial particles in homogeneous and isotropic turbulence

Ruan,

Gorman,

2024

J. Fluid Mech.

Self Cite

View full text Add to dashboard Cite

show abstract

“…2018 a ; Ruan et al. 2022). We also consider binary instantaneous collisions neglecting any particle–particle agglomeration due to electrostatic effects.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, we propose closure assumptions for the particle velocity-charge covariance and for the particle charge variance transport equations. These models are derived on the framework of the kinetic theory of rapid granular flow, with the assumption that the electrostatic force does not modify the hard-sphere collision model and that the electric field does not polarize the particles (Kolehmainen et al 2018a;Ruan et al 2022). We also consider binary instantaneous collisions neglecting any particle-particle agglomeration due to electrostatic effects.…”

Section: Introductionmentioning

confidence: 99%

Charge–velocity correlation transport equations in gas–solid flow with triboelectric effects

2023

View full text Add to dashboard Cite

This paper is dedicated to the development of particle charge and velocity second-order moment transport equations for monodisperse particles in gas flow with a tribocharging effect. The full transport equations for the particle charge–velocity covariance and the charge variance are derived in the framework of the kinetic theory of granular flow assuming that the electrostatic interaction does not modify the collision dynamics. The collision integrals are solved without presuming the form of the electric part for the particle probability density function. The full second-order transport equation model is tested in a one-dimensional periodic domain. The results show that this model is able to capture more important physical mechanisms that are neglected by simple algebraic models proposed in the past. An in-depth analysis of the transport equations is also performed. This study reveals that, for sufficiently small covariance characteristic destruction time scales, the transient and third-order moments terms can be safely neglected. In addition, two different reduced-order models are proposed: a more general algebraic model that takes into account the variance effect and a semi-algebraic model that only resolves a transport equation for the charge variance coupled with an algebraic model for the covariance. The former could, however, lead to non-physical predictions in many cases, while the latter can be a suitable alternative only for a sufficiently small interparticle collision time. Finally, a simple chart based on test case simulations is proposed to show under which conditions a semi-algebraic model could be considered as a suitable alternative.

show abstract