Triboelectric charging in single-component particle systems

Lacks, Daniel J.; Sankaran, R. Mohan

doi:10.1080/02726351.2015.1043676

Cited by 15 publications

(9 citation statements)

References 90 publications

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“…In multicomponent mixtures, the presence of positively and negatively charged particles would be expected due to the different chemical compositions of the particles. However, similar bipolar charging occurs for particles of a single material composition (see review article by Lacks and Sankaran [27]).…”

Section: Granular Materialsmentioning

confidence: 88%

An overview of advances in understanding electrostatic charge buildup in gas-solid fluidized beds

Mehrani

Murtomaa

Lacks

2017

Journal of Electrostatics

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Electrostatic charging of particles in gas-solid fluidized beds often results in operational complications in commercial processes. This paper provides a comprehensive review of the advances from the last decade in three key areas, namely the fundamental understanding of triboelectric charging, methods to measure particle charge, and experiments to elucidate particle charging processes in fluidized beds. This review underscores the need for better understanding the mechanisms of triboelectric charging in granular systems, effective online charge monitoring techniques, and experiments under industrially relevant conditions to better comprehend the problems in commercial reactors that can enable strategies to mitigate charging.

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Section: Granular Materialsmentioning

confidence: 88%

An overview of advances in understanding electrostatic charge buildup in gas-solid fluidized beds

Mehrani

Murtomaa

Lacks

2017

Journal of Electrostatics

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“…To evaluate equations (14) and (15), expressions for , and θ need to be specified. We let 1 , though note that the choice of this expression is arbitrary, and adopt it simply because it rapidly approaches at large n. We also adopt a function of the form:…”

Section: B Enhancement Factor Calculationmentioning

confidence: 99%

“…Collisions between micrometer sized charged particles/dust grains have a large influence on the behavior of many colloidal [1], aerosol [2,3], granular [4][5][6], and dusty plasma [7][8][9] systems. For example, in fluidized beds, dust storms, and volcanic plumes, particle-particle collisions lead to charge exchange (even for identical chemical composition particles [4,[10][11][12]), which can significantly alter the behavior of a particle-laden flow [13][14][15]. In aerosols and dusty plasmas, oppositely charged particles rapidly aggregate (collide and bind) with one another, while the charging of particles to sufficiently high levels of the same polarity stabilizes them against aggregation [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Collision rate coefficient for charged dust grains in the presence of linear shear

Hui

Hogan

2017

Phys. Rev. E

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Like and oppositely charged particles or dust grains in linear shear flows are often driven to collide with one another by fluid and/or electrostatic forces, which can strongly influence particle-size distribution evolution. In gaseous media, collisions in shear are further complicated because particle inertia can influence differential motion. Expressions for the collision rate coefficient have not been developed previously which simultaneously account for the influences of linear shear, particle inertia, and electrostatic interactions. Here, we determine the collision rate coefficient accounting for the aforementioned effects by determining the collision area, i.e., the area of the plane perpendicular to the shear flow defining the relative initial locations of particles which will collide with one another. Integration of the particle flux over this area yields the collision rate. Collision rate calculations are parametrized as an enhancement factor, i.e., the ratio of the collision rate considering potential interactions and inertia to the traditional collision rate considering laminar shear only. For particles of constant surface charge density, the enhancement factor is found dependent only on the Stokes number (quantifying particle inertia), the electrostatic energy to shear energy ratio, and the ratio of colliding particle radii. Enhancement factors are determined for Stokes numbers in the 0-10 range and energy ratios up to 5. Calculations show that the influences of both electrostatic interactions and inertia are significant; for inertialess (St=0) equal-sized and oppositely charged particles, we find that even at energy ratios as low as 0.2, enhancement factors are in excess of 2. For the same situation but like-charged particles, enhancement factors fall below 0.5. Increasing the Stokes number acts to mitigate the influence of electrostatic potentials for both like and oppositely charged particles; i.e., inertia reduces the enhancement factor for oppositely charged particles and increases it for like-charged particles. Uniquely, at elevated Stokes numbers with attractive potentials we find collisionless "pockets" within the collision area, which are regions completely bounded by the collision area but within which collisions do not occur. Regression equations to results are provided, enabling calculation of the enhancement factor as a function of energy ratio and Stokes number. In total, this study both leads to insight into the collision dynamics of finite-inertia, charged particles in shear flows, and provides a means to simply calculate the particle-particle collision rate coefficient.

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“…In general, contact electrification is not limited to mixtures of different materials but can also occur between particles of the same material [89][90][91][92][93][94][95]. In an agitated mixture of identical insulators, some particles carry negative charge, while others are charged positively.…”

Section: Triboelectric Charging Between Identical Materialsmentioning

confidence: 99%