Drag Correction Reference

Drag Correction Properties

The Drag Correction node is a child node of the Drag Force model.

Dimensions

The dimensionality of the drag correction (read-only).

Method

Selects the method to use for specifying the drag correction.

• Field Function
• Lockett Kirkpatrick

  This method is used for small ellipsoidal air/water bubbles with a size range in the order of 5 mm.

  The Lockett Kirkpatrick drag correction node is added.

• Richardson Zaki

  This method is the recommended option for undeformable spherical particles.

  The Richardson Zaki drag correction node is added.

• Simonnet

  This method is used for air / water bubbles in the 7-10 mm size range.

  The Simonnet drag correction node is added.

• Volume Fraction Exponent

  This method is suitable for spherical solid particles, liquid droplets, and small-diameter (spherical) bubbles.

  The Volume Fraction Exponent drag correction node is added.

  This correlation is available only when the continuous phase is viscous.

Lockett Kirkpatrick

The Lockett Kirkpatrick drag correction is a method for small ellipsoidal bubbles. It applies to air/water systems with bubble size of order 5 mm (Eotvos number around 3.3). The effect of increasing concentration is hindering.

Maximum Packing

This setting limits the maximum packing, ${\alpha }_{d,max}$ , in Eqn. (1984).

Richardson Zaki

The Richardson Zaki drag correction is a method for spherical particles, droplets, or bubbles. According to this model, the effect of increased concentration on spherical particles is that of hindering. The terminal velocity decreases faster than would be expected purely from the reduction of buoyancy force of the two-phase mixture on the particles.

This model can also cover droplets that are small enough to retain their spherical shape and whose internal viscosity is high enough for internal circulation to be negligible. This model also applies to bubbles whose surfaces are immobile due to surface contamination, as in the case of air bubbles in regular tap water.

Maximum Packing

This setting limits the maximum packing, ${\alpha }_{d,max}$ , in Eqn. (1979).

Calibration Constant A, B, C, D, N1, N2

The calibration constants A, B, C, D, $n_1$ , and $n_2$ in Eqn. (1980).

Simonnet

The Simonnet drag correction is used for air / water bubbles in the 7-10 mm size range (Eotvos number 6.6-13.4) and 0.0-0.3 volume fraction of dispersed/secondary phase range. Effects are hindering in the range 0.0-0.15 and swarming in the range 0.15-0.3.

This method has no properties.

Volume Fraction Exponent

Defines the drag correction using the Volume Fraction Exponent.

Volume Fraction Exponent (continuous)

Sets the value of $n_D$ . It is included to make sure that the drag tends to zero as the amount of the continuous phase material tends to zero, given by Eqn. (1992).

Maximum Packing

This setting limits the maximum packing, ${\alpha }_{d,max}$ , given by Eqn. (1993).