SSL Engineering Assumptions

(SSL Module Only)

Calculations done with the SSL module are based on the following assumptions:

Applicable to All Slurry Methods

  • Slurry models are empirical models developed from steady state flow data.

  • Solid particles are moving with the fluid. Stationary beds cannot be modeled. Sliding beds can be modeled with caution.

  • Dynamic mixing of slurries with different solid concentrations is not modeled.

  • Heat transfer is not modeled.

  • The settling of slurries is modeled in pipes only, and settling is not modeled within junctions or components.

Wilson, Addie, Clift Slurry Model

  • Base liquid behaves in a Newtonian viscosity manner.

  • Slurry viscosity is equivalent to the viscosity of the carrier fluid.

  • Particles below 150 μm are treated as part of the carrier fluid.

  • Minimal Slurry Calculation Method assumes all particles are in a sliding bed and none are suspended by turbulence.

  • Simplified and Detailed methods assume a sliding friction coefficient of 0.45.

  • The velocity used to calculate the friction factor in the deposition velocity limiting equation is approximated as the current pipe velocity.

4-Component Slurry Model

  • Carrier fluid component behaves in a Newtonian viscosity manner.

  • Only particles below 40 μm affect carrier fluid viscosity.

  • The deposition velocity nomograph is assumed to follow the same behavior as the Wilson, Addie, Clift nomograph.

  • The limiting equation for deposition velocity is not used.

Wasp-Durand Slurry Model

  • Carrier fluid viscosity is assumed to be Newtonian unless the Hank’s Bingham Plastic option is used.

  • Particle distribution along the vertical axis of the pipe cross-section is assumed to be continuous. Due to this, the heterogeneous gradient will be underestimated in systems with significant sliding beds.

  • All pipes are assumed to be horizontal.

  • All particle size groups are assumed to contribute to both the homogeneous and heterogeneous flow components with larger particles contributing more to the heterogeneous (Durand) portion and smaller particles contributing more to the homogeneous (vehicle) portion.