Comprehensive Guide to the Discrete Phase Model (DPM) in ANSYS FLUENT

This guide provides a detailed overview of the Discrete Phase Model (DPM) in ANSYS Fluent, covering all major components and settings available within this powerful multiphase flow simulation capability.

Discrete Phase Model Dialog Box

Interaction Settings

• One-Way Coupling: Fluid affects particles, but particles don’t affect fluid
• Two-Way Coupling: Mutual interaction between particles and fluid
• Four-Way Coupling: Includes particle-particle interactions alongside fluid-particle interactions

Particle Treatment Options

• Steady Particle Tracking: For steady-state simulations
• Unsteady Particle Tracking: For time-dependent simulations
• DPM Sources: Controls how particle effects are applied to continuous phase

Tracking Parameters

• Step Length Factor: Controls integration time step
• Max Number of Steps: Limits particle trajectory calculation
• Track Width: Visualization parameter for particle paths
• Step Length Factor (Coarse): For coarser grid regions
• Max Refinements: Controls mesh adaptation for particle tracking

Physical Models

Forces and Interactions

• Particle Radiation Interaction: Accounts for radiative heat transfer
• Thermophoretic Force: Models particle movement due to temperature gradients
• Saffman Lift Force: Accounts for lift due to shear flows
• Virtual Mass Force: Models added mass effect in accelerating/decelerating flows
• Pressure Gradient Force: Models force due to pressure variations

Surface Phenomena

• Erosion/Accretion: Predicts surface wear or material buildup
• Pressure-Dependent Boiling: For phase change simulations
• Temperature-Dependent Latent Heat: For variable heat of vaporization

Advanced Coupling

• Two-Way Turbulence Coupling: Accounts for particle effects on turbulence
• DEM Collision: Discrete Element Method for particle collisions
• Stochastic Collision: Probabilistic approach to particle interactions

Droplet Phenomena

• Coalescence: Models droplet merging
• Breakup: Models droplet splitting
• Breakup Models: TAB (Taylor Analogy Breakup), Wave Model

Injection Dialog Box

Injection Types

• Single: Individual particle injection
• Group: Multiple particles with defined properties
• Surface: Particles injected from a defined surface
• Cone: Conical spray pattern injection

Particle Types

• Massless: For flow visualization only
• Inert: Particles with mass but no phase change
• Droplet: Liquid particles that can evaporate
• Combusting: Particles that undergo combustion
• Multi-component: Particles with multiple material components

Diameter Distributions

• Linear: Uniform spacing between min/max diameters
• Uniform: Random diameters within specified range
• Rosin-Rammler: Common spray distribution
• Rosin-Rammler Logarithmic: Log-based version of Rosin-Rammler

Drag Laws

• Spherical: Standard drag for spherical particles
• Non-Spherical: For irregular particle shapes
• Stokes-Cunningham: For very small particles with slip correction
• High-Mach-Number: For supersonic flows
• Dynamic Drag: Accounts for changing particle shapes

Turbulent Dispersion Models

• Stochastic Tracking: Random walk model for turbulent fluctuations
• Cloud Tracking: Models particle clusters rather than individuals

Parcel Concept

• Computational representation where one simulated particle represents multiple physical particles

DPM Boundary Conditions

• Reflect: Particles bounce off surfaces
• Trap: Particles stick to surfaces
• Escape: Particles exit the domain
• Wall-Jet: Models impact and ejection of particles
• Wall-Film: Models liquid film formation on surfaces

This comprehensive overview covers the essential components of the DPM module in ANSYS Fluent, providing a foundation for effective multiphase flow simulation across a wide range of engineering applications.