The Electrostatics model
Electrostatic force is a force between particles exerted due to their charge, and can be either attractive or repulsive. Electrostatic forces can be included to existing kinematic forces by adding an Electrostatics model into the Particle Body Force section. Since the EDEM Electrostatic model uses Electrostatic screening, the size of a screen must be specified when using this model. Particles outside the screen will be removed from electrostatic force calculations on the central particle as shown:
The screened Coulomb force Fs is defined as:
Where q1 and q2 are the charges of two particles, r is the distance between their centres, and ε0 is the permittivity of free space (8.854 X 10-12 Fm-1). κ is an inverse of the Debye length, λD.
qe is the charge of an electron (1.602 X 10-19C)
ε is the relative permittivity of the medium. EDEM uses a value of 1, which is a relative permittivity of a vacuum.
Kb is the Boltzmann’s constant equal to 1.38 X 10-23 JK-1.
T is the temperature in Kelvin. EDEM uses a value of 295.4K.
The last term is the local charge concentration (where n is the number of particles of charge z).