Create: Scalar

Scalars are single-valued quantities used to describe local species concentrations. These local species concentrations can be linked to either the main lattice or a particle set. When linked to the main lattice, the time-evolution of the scalar field across the fluid lattice is governed by the advection-diffusion-reaction equation. This continuous-phase fluid representation can be used to model species mixing/blending processes and chemically reactive flows. When linked to a particle set, each particle is assigned an individual scalar value. This scalar value, which represents a species concentration within the particle, conveys with the particle as it moves through the domain. This discrete-phase particle representation can be used to model things like particle drying and particle curing.

Continuous phase fluid scalar fields can enter the system via a child geometry injection condition, a boundary condition, or an initial background concentration. For particle scalars, the initial scalar concentration associated with each particle can be specified as particles are added to the system.

Both lattice and particle scalar representations can participate in user-defined reactions. These reaction processes, in addition to any advection or diffusion transport processes, can cause the local species concentration to change in space and time. For lattice representations, these scalar reactions are modeled on a voxel-by-voxel basis per user-defined reaction kinetics. For particle representations, scalar reactions are modeled on a particle-by-particle basis. In both representations, the reaction kinetics can be functions of the local fluid/particle properties, species concentrations, and any other custom variables.

Representations

  • Scalar Field: Scalar fields are continuous field variables that evolve according to the advection-diffusion-reaction equation. Scalar fields are typically used to model species mixing and transport processes (e.g., blending and dispersion). The species represented by the scalar field can occupy both the fluid and the particles. As such, species contained within the fluid can interact with species in the particles via particle-scalar coupling.

  • Particle Scalar: Particle scalars are assigned to individual particles. These properties convey with each particle as it moves through the system. Particle scalars are not coupled to the fluid field but can be used to model intraparticle reactions (e.g., particle curing, protein expression).

Reaction Types

  • Fluid Reaction: Fluid reactions are applied to scalar fields and can be calculated on a voxel-by-voxel basis per a user-defined set of reaction kinetics. These kinetics can be functions of the local species concentrations, as well as the local fluid/particle properties. Reactions are solved in tandem with the advection-diffusion equation, particle advection, and the fluid transport algorithm.

  • Static Body Reaction: Static body reactions are applied to scalar fields along a static body surface. Like fluid reactions, these are calculated on a voxel-by-voxel basis using a user-defined set of reaction kinetics. However, unlike fluid reactions, which are applied to the entire fluid field, these kinetics are only applied along the solid surface.

  • Particle Reaction: Particle reactions are applied to particle fields and calculated on a particle-by-particle basis per a user-defined set of reaction kinetics. These kinetics can be functions of the species concentrations within each particle, as well as of the properties of the surrounding fluid.