Particle Reaction

Introduction

Particle body reactions represent chemical reactions that operate inside particles. The reactions are calculated on a particle-by-particle basis and can be a function of the particle properties, particle scalar values, particle custom variables, local fluid properties, as well as any global variables or parameters.

Particle reactions can also interact with aqueous scalar fields, provided the scalar field is coupled to the particles via a convection or dissolution/perception process. When a thermal field is active, particle reactions can include the effects of heat of reaction (i.e., exothermic and endothermic reactions).

Particle reactions are useful for modeling particle curing processes, intracellular reactions, particle polymerization processes, etc.

In the example below, we model a curing process wherein resin particles are converted into product particles. The curing process is driven by a miscible solvent, which is added to the top of the vessel. The curing process requires a minimum (local) solvent concentration to initiate particle conversion. Above a certain solvent threshold, the resin converts into an undesired byproduct. The competition between solvent mixing and particle-solvent exposure informs process yield and efficiency.

Property Grid

Intraparticle Reaction UDF

mol/s, g/s, or none | This UDF defines intraparticle reactions between species inside a particle. The number of output variables matches the total number of aqueous and particle scalar fields in the model. The output variables are named rate_{scalar}, where {scalar} is the dynamic name of the coupled scalar field, and rate_{pvs_p}, where {pvs_p} is the dynamic name of the particle species. Each output is a floating-point value representing the reaction rate.

Rates can be specified for all particle scalars, as well as species coupled to the scalar field. The interspecies reaction rate must have units compatible with those defined for the interparticle species concentration. Positive values indicate species production, while negative values indicate species consumption.

If a thermal field is present and the heat of reaction is enabled, an additional QDot output becomes available. Positive QDot values imply exothermic reactions, whereas negative values indicate endothermic reactions.

This is a particle-based local UDF, calculated on a particle-by-particle basis using the local particle/fluid properties.

Download Sample File: Injection

Integration

This setting defines which algorithm will be used to numerically integrate the reaction kinetics.

Euler (1st Order)

Runge-Kutta (4th Order)

Rosenbrock (Implicit)

Particle Reaction Toolbar

Context-Specific Toolbar Forms	Description
Help	The Help command launches the M-Star reference documentation in your web browser.

For a full description of each option, see Context-Specific Toolbar selections.