COMSOL 6.2 - Dielectrophoretic Force

Use the node to exert a dielectrophoretic force to the particles. Even an uncharged particle is subjected to a force in a nonuniform electric field if the particle’s permittivity is different than the permittivity of the surrounding fluid.

Supported formulations:

The force is specified via an electric potential or the electric field. The force has a different meaning depending on whether the source electric field is computed in a or study. Additionally, piecewise polynomial recovery can be used which can give a more accurate representation of the specified electric field.

The influence of the dielectrophoretic force on the particles depends on the difference in permittivity between the particles and the fluid. When the particle relative permittivity is greater than the relative permittivity of the fluid, the particles are attracted to regions where the electric field norm is greater. When the particle relative permittivity is less than the relative permittivity of the fluid, the particles are attracted to regions where the electric field norm is smaller.

The Shell subnode is available from the context menu (right-click the parent node) or from the toolbar, menu. Use it to model dielectrophoresis of particles with thin dielectric shells. If no subnodes are added, the particle is treated as a homogeneous sphere of uniform permittivity and conductivity for the purpose of computing the dielectrophoretic force.

Select an option from the list: (the default) or .

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For enter values or expressions in the table for the E (SI unit: V/m) based on space dimension. If the electric field is computed by another physics interface then it can be selected from the list.

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For enter a value or expression for V (SI unit: V). If the electric potential is computed by another physics interface then it can be selected from the list.

By default the εr (dimensionless) is taken . Select from the list to enter a value or expression.

By default the σ (SI unit: S/m) is taken . Select from the list to enter a value or expression.

Select the check box to smooth the electric field using piecewise polynomial recovery. This can give a much more accurate representation of the electric field as it uses information on adjacent mesh elements to reconstruct the field. If a coarse mesh is used to compute the field then this option can be especially useful.

Select an option from the list: or . For the dielectrophoretic force is computed using the angular frequency of the electric field computed in a previous study step. For enter the ω (SI unit: rad/s). The default value is 0.

Use the list to apply the force to specific particles. The available settings are the same as for the Force node.