Numerical analysis of frictional charging and electrostatic interaction of particles

Hu, Jiawei; Chen, Pei; Zhang, Ling; Liang, Cai; Wu, Chuanyu

doi:10.1002/aic.17444

Cited by 12 publications

(8 citation statements)

References 40 publications

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“…To determine the contact forces for elastic particles, Hertz theory is used to model the normal contact, while the theory of Mindlin and Deresiewicz is applied to calculate the tangential forces. 43,44 The translational and rotational movements of a particle are expressed by…”

Section: Volume Expansion and Softening During Swellingmentioning

confidence: 99%

“…E * and r * are effective elastic modulus and the effective radius in contact; E a , E b ,

ν_{a}

ν_{b}

r_{p, a}

, and

r_{p, b}

are the elastic moduli, Poisson's ratios and radii of the contacted objects, respectively. In addition, according to the overlap and the effective radius in contact, the radius of the contact area can be calculated as 43,44

r_{italiccon} = \sqrt{δ_{n} r^{*} .}

…”

Section: Dem‐cfd Modelmentioning

confidence: 99%

“…where f c , f lp , m p g, I, ω, and T are the contact force, liquid-particle interaction force, gravitational force, moment of inertia, angular velocity, and torque of the particle, respectively. The normal contact force F n between two contacted objects is calculated based on Hertz theory as 43,44…”

Section: Volume Expansion and Softening During Swellingmentioning

confidence: 99%

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DEM‐CFD analysis of swelling behaviors of binary particle systems with a microscopic diffusion model

Hu,

Li,

Zhang

et al. 2023

AIChE Journal

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Swelling, that is, volumetric expansion, of particles is ubiquitous in many industrial systems containing both swellable particles and non‐swellable particles. However, the interactions between these two types of particles and the internal stress distribution within the binary particle systems are not yet fully understood. The dynamic behavior of binary mixtures with both swellable and non‐swellable particles was explored for the first time in this study by employing a microscopic diffusion swelling model that considers the change in microstructure of swelling particles implemented in the discrete element method coupled with computational fluid dynamics (DEM‐CFD). The expansion of particle bed consists of super absorbent polymers (SAPs) particles, that is, the swellable particles, and polyformaldehyde (POM) particles, that is, the non‐swellable particles, in a rectangle container is then analyzed experimentally and numerically. The results show that a tapered pattern of SAP particles and an arch pattern of POM particles are formed during the swelling process. The Lacey index is used to quantify the mixing degree of the binary particle system, which increases with time until the POM particle layer is fully encompassed by SAP particles. The mean stress distribution within the particle system is also examined, revealing that the swollen SAP particles migrate upward through a “low‐stress channel,” pushing the POM particles in the central area outward. Moreover, it is found that, for case with a relative low friction, SAP particles penetrate the POM particle layer along the container walls, while for the cases with relative high friction, SAP particles penetrate the POM particle layers through the central regions of the container.

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Section: Volume Expansion and Softening During Swellingmentioning

confidence: 99%

“…E * and r * are effective elastic modulus and the effective radius in contact; E a , E b ,

ν_{a}

ν_{b}

r_{p, a}

, and

r_{p, b}

r_{italiccon} = \sqrt{δ_{n} r^{*} .}

…”

Section: Dem‐cfd Modelmentioning

confidence: 99%

See 1 more Smart Citation

DEM‐CFD analysis of swelling behaviors of binary particle systems with a microscopic diffusion model

Hu,

Li,

Zhang

et al. 2023

AIChE Journal

Self Cite

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“…Coupled DEM-CFD (Computational Fluid Dynamics) studies showed the detailed motion of particles from the initial dispersion in air through to the mouthpiece [ 21 , 22 , 23 , 24 , 25 ]. In the last decade, model formulations have been introduced to extend the particle-scale contact tracking capability of DEM with surface–surface charge transfer and physical electrostatic interaction models (see, e.g., [ 26 , 27 , 28 ]), allowing triboelectric charging phenomena at the particle scale to be studied [ 27 , 29 , 30 , 31 , 32 , 33 ]. Naik et al [ 34 ] studied the triboelectrification of binary mixtures of drug and excipient in a blender.…”

Section: Introductionmentioning

confidence: 99%

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

2023

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The generation and accumulation of an electrostatic charge from handling pharmaceutical powders is a well-known phenomenon, given the insulating nature of most APIs (Active Pharmaceutical Ingredients) and excipients. In capsule-based DPIs (Dry Powder Inhalers), the formulation is stored in a gelatine capsule placed in the inhaler just before inhalation. The action of capsule filling, as well as tumbling or vibration effects during the capsule life cycle, implies a consistent amount of particle–particle and particle–wall contacts. A significant contact-induced electrostatic charging can then take place, potentially affecting the inhaler’s efficiency. DEM (Discrete Element Method) simulations were performed on a carrier-based DPI formulation (salbutamol–lactose) to evaluate such effects. After performing a comparison with the experimental data on a carrier-only system under similar conditions, a detailed analysis was conducted on two carrier–API configurations with different API loadings per carrier particle. The charge acquired by the two solid phases was tracked in both the initial particle settling and the capsule shaking process. Alternating positive–negative charging was observed. Particle charging was then investigated in relation to the collision statistics, tracking the particle–particle and particle–wall events for the carrier and API. Finally, an analysis of the relative importance of electrostatic, cohesive/adhesive, and inertial forces allowed the importance of each term in determining the trajectory of the powder particles to be estimated.

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“…In the screw feeding process of food powder, the contact, collision, friction, and separation between powder particles and between the particles and the screw feeder cause a large amount of static electricity to accumulate in the powder (Hu et al, 2021). The powder carrying static electricity is easy to be adsorbed on the inner and outer walls of the packaging bag, causing poor quantitative accuracy of the packaging and incomplete heat sealing of the packaging bag; more serious is the accumulation of powder static electricity may cause the powder to catch fire, explosion, and other safety hazards (Bailey, 1984; Beloni & Dreizin, 2009, 2011; Boland & Geldart, 1972).…”

Section: Introductionmentioning

confidence: 99%

Analysis of static electricity generation and elimination in the process of food powder screw feeding

Shen

Wang

et al. 2022

J Food Process Engineering

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The static electricity in the powder can easily cause poor packaging accuracy, incomplete heat‐sealing of the packaging bag and certain safety hazards. Therefore, the electrostatic generation and elimination of wheat flour and wheat starch were studied in the process of powder screw feeding. Firstly, taking powder particle size, screw speed and conveying distance as influencing factors, the law of static electricity generation in the process of powder screw conveying is studied. Then, an adjustable DC power supply and an ion fan were used to apply voltage and ion wind during the powder screw feeding process to study the elimination of powder static electricity. The research results show that the electrostatic charge of wheat flour and wheat starch is positive. The greater the screw speed, the more severe the powder collision and friction, and the greater the increase in powder charge‐to‐mass ratio. The larger the conveying distance, the greater the increase in the powder‐to‐mass ratio, and when the conveying distance reaches 5200 mm, the experimental powder‐to‐mass ratio tends to be stable. The gain and loss of the charge of wheat starch with small particle size is obviously greater than that of wheat flour with large particle size. The ability and stability of adding ion wind at the outlet of the screw feeder to eliminate static electricity are obviously stronger than the ability and stability of adding voltage to eliminate static electricity. Practical applications The static electricity generated in the process of screw conveying and feeding causes trouble to the packaging weighing, packaging sealing and safety production of powder. Therefore, this paper studies the electric characteristics of food powder in the process of screw transportation and the influence of various factors on the electrostatic generation law, and also through experiments to compare the two methods of electrostatic elimination. This study provides ideas and references for reducing the generation and elimination of static electricity in the process of screw transportation of food powder, so as to improve the packaging accuracy, packaging quality and reduce safety risks in actual industrial production.

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Numerical analysis of frictional charging and electrostatic interaction of particles

Cited by 12 publications

References 40 publications

DEM‐CFD analysis of swelling behaviors of binary particle systems with a microscopic diffusion model

DEM‐CFD analysis of swelling behaviors of binary particle systems with a microscopic diffusion model

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

Analysis of static electricity generation and elimination in the process of food powder screw feeding

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