Since the concentration of particles is an important factor in the calculation of the effective viscosity for the mixture, we may use the granular viscosity to get a value for the viscosity of the suspension. The volume weighted averaged for the viscosity would now contain shear viscosity arising from particle momentum exchange due to translation and collision.

The collisional and kinetic parts, and the optional frictional part, are added to give the solids shear viscosity:

(14–139)

Refer to Solids Pressure for definitions of the constants used in granular flow.

 

14.4.8.1. Collisional Viscosity

The collisional part of the shear viscosity is modeled as [205], [640].

(14–140)

 

14.4.8.2. Kinetic Viscosity

Ansys Fluent provides two expressions for the kinetic viscosity.

The default expression is from Syamlal et al. [640]:

(14–141)

The following optional expression from Gidaspow et al. [205] is also available:

(14–142)