Expand/Collapse all
1. Basic Capabilities Modeling
1.1. Domains
1.2. Physical Models
1.2.1. Steady State and Transient Flows
1.2.2. Mesh Deformation
1.2.2.1. None
1.2.2.2. Regions of Motion Specified
1.2.2.2.1. Displacement Relative To
1.2.2.2.2. Mesh Stiffness
1.2.2.2.2.1. Increase Near Small Volumes
1.2.2.2.2.2. Increase Near Boundaries
1.2.2.2.2.3. Blended Distance and Small Volumes
1.2.2.2.2.4. Value (Specified Stiffness)
1.2.2.2.3. Mesh Motion Options
1.2.2.2.3.1. Conservative Interface Flux
1.2.2.2.3.2. Unspecified
1.2.2.2.3.3. Stationary
1.2.2.2.3.4. Specified Displacement
1.2.2.2.3.5. Specified Location
1.2.2.2.3.6. Periodic Displacement
1.2.2.2.3.7. Parallel to Boundary
1.2.2.2.3.8. Surface of Revolution
1.2.2.2.3.9. System Coupling
1.2.2.2.3.10. Rigid Body Solution
1.2.2.3. Periodic Regions of Motion
1.2.2.3.1. Periodic Regions of Motion: Complex Displacement
1.2.2.3.1.1. Boundary conditions
1.2.2.3.1.2. Complex Displacement Solution
1.2.2.4. Junction Box Routine
1.2.3. Laminar Flow
1.2.4. Turbulence and Turbulence Models
1.2.5. Heat Transfer
1.2.5.1. None
1.2.5.2. Isothermal
1.2.5.3. Thermal Energy
1.2.5.4. Total Energy
1.2.5.5. Turbulent Flux Closure
1.2.6. Conjugate Heat Transfer
1.2.7. Compressible Flow
1.2.7.1. Mixed Subsonic/Supersonic Boundaries
1.2.8. Setting a Reference Pressure
1.2.9. Buoyancy
1.2.9.1. Full Buoyancy Model (Density Difference)
1.2.9.2. Boussinesq Model
1.2.9.3. Buoyancy and Pressure
1.2.9.4. Buoyancy In Rotating Domains
1.2.10. Immersed Solids
1.2.10.1. Immersed Boundary Tracking
1.2.10.2. Limitations to using Immersed Solids
1.2.11. Multicomponent Flow
1.2.11.1. Assumptions About Multicomponent Flow
1.2.11.2. Multicomponent Flow Terminology
1.2.11.2.1. Pure Substance
1.2.11.2.2. Component
1.2.11.2.3. Multicomponent Fluid
1.2.11.2.4. Fluid
1.2.11.2.5. Additional Variable
1.2.11.2.6. Ideal Mixture
1.2.11.2.7. Transport Equation
1.2.11.2.8. Constraint Equation
1.2.11.2.9. Algebraic Equation
1.2.11.3. Multicomponent Flow Examples
1.2.11.3.1. Example 1: Multicomponent Multiphase
1.2.11.3.2. Example 2: Smoke in Air
1.2.11.4. Component Domain Settings
1.2.11.4.1. Algebraic Slip
1.2.11.4.2. Kinematic Diffusivity
1.2.11.4.3. Turbulent Flux Closure
1.2.11.5. Boundary Conditions
1.2.11.6. Multicomponent Energy Diffusion
1.2.12. Additional Variables
1.2.12.1. Transported and Algebraic Additional Variables
1.2.12.1.1. Kinematic Diffusivity
1.2.12.1.2. Turbulent Flux Closure
1.2.12.1.3. Volumetric and Specific Additional Variable
1.2.12.1.4. Additional Variables In Units Other Than Mass
1.2.12.1.5. Unspecified Additional Variables
1.2.12.1.6. Tensor Type
1.2.12.2. Dynamic Additional Variables
1.2.13. Non-Newtonian Flow
1.2.14. Coordinate Frames
1.2.14.1. Global Coordinate Frame (Coord 0)
1.2.14.2. Local Coordinate Frames
1.2.14.3. Cartesian Coordinate Frames
1.2.15. Rotating Frames of Reference (RFR)
1.2.15.1. Alternate Rotation Model
1.2.16. Electric Field
1.3. Sources
1.3.1. Locators for Sources
1.3.1.1. Boundary Sources
1.3.1.2. Subdomains
1.3.1.3. Injection Regions
1.3.1.4. Source Points
1.3.2. Types of Sources
1.3.2.1. General Sources
1.3.2.1.1. Source Coefficient / Total Source Coefficient
1.3.2.2. Momentum Sources
1.3.2.2.1. Isotropic and Directional Loss Models
1.3.2.2.2. General Momentum Source
1.3.2.2.2.1. Postprocessing the Momentum Sources
1.3.2.2.3. Immersed Solids Sources
1.3.2.3. Mass (Continuity) Sources
1.3.2.3.1. Mass (Continuity) Source Coefficients
1.3.2.4. Bulk Sources
1.3.2.5. Solid Sources
1.3.2.6. Radiation Sources
1.3.2.7. Particle User Sources
1.3.3. Multiplying Sources by Porosity
1.4. Material Properties
1.4.1. CEL Expressions
1.4.2. Coordinate Frame
1.4.3. Equation of State
1.4.3.1. Option
1.4.3.1.1. Value
1.4.3.1.2. Ideal Gas
1.4.3.1.3. Real Gas
1.4.3.1.4. IAPWS Library
1.4.3.2. Molar Mass
1.4.4. Specific Heat Capacity
1.4.4.1. Value
1.4.4.2. NASA Format
1.4.4.3. Zero Pressure Polynomial
1.4.4.4. Real Gas
1.4.4.5. Reference State Properties
1.4.4.5.1. Reference Temperature and Reference Pressure
1.4.4.5.2. Reference Specific Enthalpy and Entropy
1.4.5. Density and Specific Heat Dependencies
1.4.6. Table Generation Pressure and Temperature Limits
1.4.7. Transport Properties
1.4.7.1. Dynamic Viscosity
1.4.7.1.1. Value
1.4.7.1.2. Rigid Non Interacting Sphere and Interacting Sphere Models
1.4.7.1.3. Non-Newtonian Model
1.4.7.1.4. Ideal Mixture
1.4.7.1.5. Sutherland’s Formula
1.4.7.2. Thermal Conductivity
1.4.7.2.1. Sutherland’s Formula
1.4.7.2.2. Modified Euken Model
1.4.8. Radiation Properties
1.4.9. Buoyancy Properties
1.4.9.1. Thermal Expansivity
1.4.10. Electromagnetic Properties
1.4.10.1. Electrical Conductivity
1.4.10.2. Magnetic Permeability
1.4.11. Library Materials
1.4.11.1. Adding to the MATERIALS file
1.5. Mixture Properties (Fixed, Variable, Reacting)
1.5.1. Equation of State/Density
1.5.2. Molar Mass
1.5.3. Specific Heat Capacity
1.5.4. Electromagnetic Properties
1.6. Efficiency Calculation
1.6.1. Isentropic Efficiency and Total Enthalpy
1.6.2. Polytropic Efficiency
1.6.3. Activating Efficiency Output
1.6.3.1. CFX-Solver Manager Output Variables
1.6.3.2. Results File Output Variables
1.6.4. Restrictions
1.7. Wall Condensation Model
1.7.1. CFX-Pre Set-up
1.7.1.1. Domain Fluid Model Specification
1.7.1.2. Boundary Condition Specification
1.7.1.3. Restrictions
1.7.1.4. Convergence Tip
1.7.2. Condensation Mass Flux in CFD-Post
2. Boundary Condition Modeling
2.1. The Purpose of Boundary Conditions
2.2. Available Boundary Conditions
2.2.1. Fluid Boundaries
2.2.2. Solid Boundaries
2.3. Using Boundary Conditions
2.3.1. Specifying Well-Posed Boundary Conditions
2.3.2. Recommended Configurations of Boundary Conditions
2.3.3. Using Inlets, Outlets and Openings
2.3.3.1. Inlets
2.3.3.2. Outlets
2.3.3.3. Openings
2.3.3.4. Using Pressure Specified Boundaries with Buoyant Flows
2.3.4. Using CEL Expressions With Boundary Conditions
2.4. Inlet
2.4.1. Mesh Motion
2.4.2. Inlet (Subsonic)
2.4.2.1. Mass and Momentum
2.4.2.1.1. Normal Speed
2.4.2.1.2. Cartesian Velocity Components
2.4.2.1.3. Cylindrical Velocity Components
2.4.2.1.4. Mass Flow Rate
2.4.2.1.5. Total Pressure (Stable)
2.4.2.1.6. Stationary Frame Total Pressure (Stable)
2.4.2.1.7. Static Pressure
2.4.2.1.8. Fluid Velocity
2.4.2.2. Flow Direction
2.4.2.3. Turbulence
2.4.2.3.1. Default Intensity and Autocompute Length Scale
2.4.2.3.2. Intensity and Autocompute Length Scale
2.4.2.3.3. Intensity and Length Scale
2.4.2.3.4. Low (Intensity = 1%)
2.4.2.3.5. Medium (Intensity = 5%)
2.4.2.3.6. High (Intensity = 10%)
2.4.2.3.7. Specified Intensity and Eddy Viscosity Ratio
2.4.2.3.8. k and Epsilon
2.4.2.3.9. Zero Gradient
2.4.2.4. Heat Transfer
2.4.2.4.1. Static Temperature
2.4.2.4.2. Total Temperature
2.4.2.4.3. Stat. Frame Total Temperature
2.4.2.4.4. Total Enthalpy
2.4.2.4.5. Stationary Frame Total Enthalpy
2.4.2.5. Thermal Radiation
2.4.2.5.1. Radiative Heat Flux (P1 Model)
2.4.2.5.2. Radiation Intensity (P1 Model)
2.4.2.5.3. External Blackbody Temperature
2.4.2.5.4. Local Temperature
2.4.2.5.5. Sources (Discrete Transfer and Monte Carlo models)
2.4.2.6. Transported Additional Variables at an Inlet
2.4.3. Inlet (Supersonic)
2.4.3.1. Mass and Momentum
2.4.4. Inlet (Mixed Subsonic-Supersonic)
2.4.4.1. Supported Material Types
2.4.4.2. Mass and Momentum
2.4.4.2.1. Cartesian Velocity Components and (Total) Pressure
2.4.4.2.2. Cylindrical Velocity Components and (Total) Pressure
2.4.4.2.3. Normal Speed and (Total) Pressure
2.4.4.3. Heat Transfer
2.4.4.3.1. Static Temperature
2.4.4.3.2. Total Temperature
2.4.4.3.3. Total Enthalpy
2.4.4.4. Initial Guess Recommendation
2.5. Outlet
2.5.1. Mass and Momentum
2.5.1.1. Static Pressure
2.5.1.2. Normal Speed
2.5.1.3. Cartesian Velocity Components
2.5.1.4. Cylindrical Velocity Components
2.5.1.5. Average Static Pressure
2.5.1.5.1. Average Over Whole Outlet
2.5.1.5.2. Average Above Specified Radius
2.5.1.5.3. Average Below Specified Radius
2.5.1.5.4. Circumferential
2.5.1.5.5. Radial Equilibrium
2.5.1.6. Mass Flow Rate (Bulk Mass Flow Rate for Multiphase)
2.5.1.7. Exit Corrected Mass Flow Rate
2.5.1.8. Mass Flow Outlet Constraint
2.5.1.8.1. Pressure Shape Unconstrained
2.5.1.8.2. Uniform Mass Flux
2.5.1.8.3. Pressure Shape Constrained
2.5.1.8.3.1. Circumferential Pressure Averaging
2.5.1.9. Degassing Condition (Multiphase only)
2.5.1.10. Fluid Velocity (Multiphase only)
2.5.1.11. Supercritical (Multiphase only)
2.5.2. Turbulence, Heat Transfer, and Additional Variables
2.5.3. Thermal Radiation
2.5.4. Mesh Motion
2.5.5. Outlet (Supersonic)
2.6. Opening
2.6.1. Mass and Momentum
2.6.1.1. Cartesian Velocity Components
2.6.1.2. Cylindrical Velocity Components
2.6.1.3. Opening Pressure and Direction
2.6.1.4. Static Pressure and Direction
2.6.1.5. Entrainment
2.6.1.6. Fluid Velocity
2.6.2. Loss Coefficient
2.6.2.1. For a Pressure-Specified Opening
2.6.2.2. For a Static-Pressure-Specified Opening
2.6.3. Heat Transfer
2.6.4. Turbulence
2.6.5. Thermal Radiation
2.6.6. Additional Variables
2.6.7. Mesh Motion
2.7. Wall
2.7.1. Mass and Momentum
2.7.1.1. No Slip Wall
2.7.1.2. Free Slip Wall
2.7.1.3. Finite Slip Wall
2.7.1.4. Specified Shear
2.7.1.5. Counter-rotating Wall
2.7.1.6. Rotating Wall
2.7.2. Wall Roughness
2.7.3. Wall Contact Model
2.7.4. Wall Adhesion
2.7.5. Heat Transfer
2.7.5.1. Adiabatic
2.7.5.2. Fixed Temperature
2.7.5.3. Heat Flux and Wall Heat Flux
2.7.5.4. Heat Transfer Coefficient and Wall Heat Transfer Coefficient
2.7.5.5. System Coupling
2.7.5.6. Results File Variables for Postprocessing
2.7.5.6.1. Wall Temperature (Tw )
2.7.5.6.2. Wall Heat Flux and Heat Flux (qw )
2.7.5.6.3. Wall Heat Transfer Coefficient (hc ) and Wall Adjacent Temperature (Tnw )
2.7.5.6.4. Wall External Heat Transfer Coefficient and Wall External Temperature
2.7.6. Mesh Motion
2.7.7. Thermal Radiation
2.7.7.1. Opaque
2.7.7.2. Sources
2.7.8. Equations Governing Additional Variables
2.8. Symmetry Plane
2.8.1. Mesh Motion
2.9. Profile Boundary Conditions
2.9.1. Using a Profile From One Location at Another Location
2.9.2. Standard Variable Names
2.9.3. Non-Standard Variable Names
2.9.4. Custom Variables
2.9.5. Using r-Theta Profiles
2.9.6. Data Interpolation Method
2.9.7. Extracting Profile Data from Results Files
2.10. General Non-Reflecting Boundary Conditions
2.10.1. Overview
2.10.2. Restrictions and Limitations
2.10.3. Theory
2.10.4. Acoustic Reflectivity Settings in CFX-Pre
2.11. Limitations
3. Initial Condition Modeling
3.1. Setting the Initial Conditions in CFX-Pre
3.1.1. Automatic
3.1.2. Automatic with Value
3.1.3. Using Expressions with Initial Conditions
3.2. Initialization Parameters
3.2.1. Coordinate Frame
3.2.2. Frame Type
3.2.2.1. Considerations for Multiple Domains and Global Initialization
3.2.3. Velocity Type
3.2.3.1. Cartesian Coordinate Frame, Cartesian Velocity Components
3.2.3.2. Cartesian Coordinate Frame, Cylindrical Velocity Components
3.2.3.3. Cylindrical Coordinate Frame, Cartesian Velocity Components
3.2.3.4. Cylindrical Coordinate Frame, Cylindrical Velocity Components
3.2.4. Cartesian Velocity Components
3.2.4.1. Automatic Values
3.2.4.2. Recommended Values
3.2.5. Cylindrical Velocity Components
3.2.5.1. Automatic Values
3.2.5.2. Recommended Values
3.2.6. Velocity Scale
3.2.7. Velocity Fluctuation
3.2.8. Static Pressure
3.2.8.1. Automatic Values
3.2.8.2. Recommended Values
3.2.9. Temperature
3.2.9.1. Automatic Values
3.2.9.2. Recommended Values
3.2.10. K (Turbulent Kinetic Energy)
3.2.10.1. Automatic Values
3.2.10.2. Recommended Values
3.2.11. Epsilon (Turbulence Eddy Dissipation)
3.2.11.1. Automatic Values
3.2.11.2. Recommended Values
3.2.11.3. Manual Specification
3.2.12. Omega (Turbulence Eddy Frequency)
3.2.12.1. Automatic Values
3.2.12.2. Recommended Values
3.2.12.3. Manual Specification
3.2.13. Reynolds Stress Components
3.2.14. Initialization of Additional Variables
3.2.15. Component
3.2.16. Volume Fraction
3.2.17. Radiation Intensity
3.2.18. Initialization of Solid Domains
3.2.19. Initial Conditions for a Multiphase Simulation
3.2.19.1. Volume Fraction
3.2.19.2. Velocity
3.2.20. Initialization Advice
3.3. Reading the Initial Conditions from a File
3.3.1. Using Configuration Results to Provide Initial Values
3.3.2. Continuing the History
3.3.3. Using Multiple Files to Provide Initial Conditions
3.3.4. Using the Mesh from the Initial Values File
3.3.5. Using an Initial Values File that Contains Particles
3.4. Using the CFX-Interpolator
3.4.1. Interpolating from a Single File
3.4.1.1. Mapping Data from the Source File to the Target File
3.4.2. Interpolating from Multiple Files
3.4.3. Interpolation Mapping
3.4.3.1. Defining Transformations for use in Interpolation Mapping Alignment Transformations
3.4.3.2. Creating Interpolation Mapping Objects
3.4.4. Adjusting the Bounding Box Tolerance
3.4.5. Interpolating Onto a Solver Input File with Results Fields
3.4.6. Miscellaneous Limitations of the CFX-Interpolator
3.4.7. Using the CFX-Interpolator to Calculate Difference Variables
4. Turbulence and Near-Wall Modeling
4.1. Turbulence Models
4.1.1. The Laminar Model
4.1.2. The Zero Equation Model
4.1.3. The k-epsilon Model
4.1.4. The RNG k-epsilon Model
4.1.5. The k-omega and SST Models
4.1.5.1. GEKO model
4.1.6. Curvature Correction for Two-Equation Models
4.1.7. Corner Correction
4.1.8. The Reynolds Stress Model
4.1.9. Omega-Based Reynolds Stress Models
4.1.10. Explicit Algebraic Reynolds Stress Model
4.1.11. Ansys CFX Laminar-Turbulent Transition Models
4.1.11.1. Estimating when the Transition Model Should be Used
4.1.11.2. Grid Requirements
4.1.11.3. Specifying Inlet Turbulence Levels
4.1.11.4. Summary
4.1.12. The Large Eddy Simulation Model (LES)
4.1.12.1. Using the LES model in CFX
4.1.12.2. Introduction to LES
4.1.12.3. When to use LES
4.1.12.4. Setting up an LES Simulation
4.1.12.4.1. Geometry for LES
4.1.12.4.2. Meshing
4.1.12.4.3. Boundary Layers
4.1.12.4.4. Analysis Type
4.1.12.4.5. Domains
4.1.12.4.6. LES Boundary Conditions: Inlet
4.1.12.4.7. LES Boundary Conditions: Outlets and Openings
4.1.12.4.8. LES Initialization
4.1.12.4.9. LES Solver Control
4.1.12.4.10. LES Timestep Considerations
4.1.12.5. Solver Memory
4.1.12.6. Useful Values For LES Runs
4.1.12.6.1. Statistical Reynolds Stresses
4.1.12.6.2. Delaying the Start of Reynolds Stress Calculations
4.1.13. The Detached Eddy Simulation Model (DES)
4.1.13.1. Using the Detached Eddy Simulation Model in CFX
4.1.13.1.1. When to use DES
4.1.13.2. Setting up a DES Simulation
4.1.13.2.1. Geometry for DES
4.1.13.2.2. Meshing Requirements for DES
4.1.13.2.3. DES Timestep Considerations
4.1.13.2.4. Boundary Conditions
4.1.13.2.5. DES Initialization
4.1.13.2.6. Monitoring a DES Simulation
4.1.13.3. Limitations/Concerns of Using the DES Model
4.1.14. The Stress-Blended Eddy Simulation (SBES) Model
4.1.15. The Scale-Adaptive Simulation (SAS)
4.1.15.1. Using the Scale Adaptive Simulation model in CFX
4.1.16. Buoyancy Turbulence
4.2. Modeling Flow Near the Wall
4.2.1. Standard Wall Functions
4.2.2. Scalable Wall Functions
4.2.2.1. Shear Velocity Scaling Model
4.2.3. Automatic Near-Wall Treatment for Omega-Based Models
4.2.4. Treatment of Rough Walls
4.2.5. Solver Yplus and Yplus
4.2.6. Guidelines for Mesh Generation
4.2.6.1. Minimum Node Spacing
4.2.6.1.1. Determination of the Near Wall Spacing
4.2.6.2. Minimum Number of Nodes
4.2.6.2.1. Goal
4.2.6.2.2. Formulation
5. Domain Interface Modeling
5.1. Overview of Domain Interfaces
5.2. Interface Type
5.3. Interface Models
5.3.1. Translational Periodicity
5.3.2. Rotational Periodicity
5.3.3. General Connection
5.3.3.1. Frame Change/Mixing Model
5.3.3.1.1. None
5.3.3.1.2. Frozen Rotor
5.3.3.1.2.1. Rotational Offset
5.3.3.1.3. Stage (Mixing Plane)
5.3.3.1.3.1. Pressure Profile Decay
5.3.3.1.3.2. Downstream Velocity Constraint
5.3.3.1.3.3. Implicit Stage Averaging
5.3.3.1.4. Transient Rotor-Stator
5.3.3.2. Pitch Change
5.3.3.2.1. None
5.3.3.2.2. Automatic
5.3.3.2.3. Value
5.3.3.2.4. Specified Pitch Angles
5.3.4. Mass and Momentum Models
5.3.4.1. Translational Periodicity
5.3.4.2. General Connection
5.3.4.2.1. Specified Pressure Change
5.3.4.2.2. Specified Mass Flow Rate
5.3.4.3. Further Comments
5.4. Mesh Connection Options
5.4.1. Automatic Connections
5.4.2. Direct (One-to-One) Connections
5.4.3. GGI (General Grid Interface) Connections
5.4.3.1. Non-overlap Boundary Conditions
5.4.3.2. Conditional Connections
5.4.4. Mesh Connection Recommendations
5.5. Defining Domain Interfaces as Thin Surfaces
5.5.1. Modeling Thin Surfaces: Overview
5.6. Recommendations For Using Domain Interfaces
5.6.1. Using Domain Interfaces
5.6.2. Using Multiple Domain Interfaces
5.6.3. Using Domain Interfaces in Turbomachinery Applications
5.6.3.1. Case 1: Impeller/Volute
5.6.3.2. Case 2: Step change between rotor and stator
5.6.3.3. Case 3: Blade Passage at or close to the edge of a domain
5.6.3.4. Case 4: Blade Passage at or close to the edge of a domain
5.6.3.5. Case 5: Blade with thick trailing edge
5.7. Automatic Creation and Treatment of Domain Interfaces
6. Turbomachinery Blade Row Modeling
6.1. Transient Blade Row Modeling
6.1.1. Transient Blade Row Modeling Terminology
6.1.1.1. Abbreviations Used in this Document
6.1.2. Setting up a Transient Blade Row Model
6.1.2.1. Setting up Monitors to Check Results
6.1.3. Running and Postprocessing a Simulation that uses a Transient Blade Row Model
6.1.3.1. Stopping and then Restarting Simulations with an Increased Number of Time Steps Per Period
6.1.4. Profile Transformation
6.1.5. Time Transformation
6.1.5.1. Time Transformation: Workflow Requirements
6.1.6. Fourier Transformation
6.1.6.1. Fourier Transformation: Workflow Requirements
6.1.7. Guidelines for Using Transient Blade Row Features
6.1.7.1. General Setup Guidelines
6.1.7.2. Guidelines for using the Time Transformation Feature
6.1.7.3. Guidelines for using the Fourier Transformation Feature
6.1.7.4. General Postprocessing Guidelines
6.1.8. Use Cases
6.1.8.1. Case 1: Transient Rotor Stator Single Stage
6.1.8.1.1. Profile Transformation and Fourier Transformation using Harmonic Analysis
6.1.8.2. Case 2: Flow Boundary Disturbance
6.1.8.2.1. Flow Boundary Disturbance using Harmonic Analysis
6.1.8.2.2. Multiple Disturbances
6.1.8.3. Case 3: Blade Flutter
6.1.8.3.1. Setting Up a Blade Flutter Simulation
6.1.8.3.2. Running a Blade Flutter Simulation
6.1.8.3.3. Blade Flutter using Harmonic Analysis
6.1.8.4. Case 4: Harmonic Forced Response
6.1.8.5. Case 5: Transient Rotor Stator Multi-Stage Cases
6.1.8.5.1. Modeling a Single-pitch-ratio Multistage Turbomachine using the Time Transformation Method
6.1.8.5.2. Modeling 1.5 Stages with Two Different Pitch Ratios using the Time Transformation Method
6.1.8.5.3. Modeling a multistage turbomachine with Time Transformation TRS and other interfaces: Profile Transformation & Stage
6.1.8.5.4. Modeling a multistage turbomachine with Time Transformation TRS and single-sided Time Transformation interfaces (STT-TRS)
6.1.8.6. Case 6: Transient Rotor Stator Cases with Asymmetric Flow
6.1.8.6.1. Modeling an Impeller in a Vaneless Volute
6.1.8.6.2. Modeling an Impeller in a Vaned Volute
6.2. Blade Film Cooling
6.2.1. Options for Modeling Blade Film Cooling
6.2.1.1. Modeling Blade Film Cooling with Injection Regions
7. Multiphase Flow Modeling
7.1. Multiphase Terminology
7.1.1. Multiphase Flow
7.1.2. Eulerian-Eulerian
7.1.3. Inhomogeneous Multiphase Flow
7.1.4. Homogeneous Multiphase Flow
7.1.5. Multicomponent Multiphase Flow
7.1.6. Volume Fraction
7.1.7. Free Surface Flow
7.1.8. Surface Tension
7.2. Multiphase Examples
7.2.1. Water Droplets in Air
7.2.2. Air Bubbles in Water
7.2.3. Gas-Solid and Liquid-Solid Flow
7.2.4. Three-Phase Flow
7.2.5. Polydispersed Flow
7.3. Eulerian-Eulerian Multiphase Versus Particle Transport
7.4. Specifying Fluids for Multiphase Flow
7.4.1. Morphology
7.4.1.1. Continuous Fluid
7.4.1.2. Dispersed Fluid
7.4.1.3. Dispersed Solid
7.4.1.4. Particle Transport Fluid
7.4.1.5. Particle Transport Solid
7.4.1.6. Polydispersed Fluid
7.4.1.7. Droplets (Phase Change)
7.4.2. Mean Diameter
7.4.3. Minimum Volume Fraction
7.4.4. Maximum Packing
7.5. The Homogeneous and Inhomogeneous Models
7.5.1. The Inhomogeneous (Interfluid Transfer) Model
7.5.1.1. The Particle Model
7.5.1.2. The Mixture Model
7.5.1.3. The Free Surface Model
7.5.2. The Homogeneous Model
7.6. Buoyancy in Multiphase Flow
7.6.1. Fluid Buoyancy Model
7.6.1.1. Density Difference
7.6.1.2. Boussinesq
7.7. Multicomponent Multiphase Flow
7.8. Interphase Momentum Transfer Models
7.8.1. Interphase Drag
7.8.1.1. Interphase Drag for the Particle Model
7.8.1.1.1. Specifying a Drag Coefficient
7.8.1.1.2. Sparsely Distributed Solid Particles
7.8.1.1.2.1. Sparsely Distributed Solid Particles: Schiller Naumann Drag Model
7.8.1.1.3. Densely Distributed Solid Particles
7.8.1.1.3.1. Densely Distributed Solid Particles: Wen Yu Drag Model
7.8.1.1.3.2. Densely Distributed Solid Particles: Gidaspow Drag Model
7.8.1.1.4. Sparsely Distributed Fluid Particles (drops and bubbles)
7.8.1.1.4.1. Sparsely Distributed Fluid Particles: Ishii-Zuber Drag Model
7.8.1.1.4.2. Sparsely Distributed Fluid Particles: Grace Drag Model
7.8.1.1.4.3. Sparsely Distributed Fluid Particles: Availability
7.8.1.1.5. Densely Distributed Fluid Particles
7.8.1.1.5.1. Densely Distributed Fluid Particles: Ishii-Zuber Drag Model
7.8.1.1.5.2. Densely Distributed Fluid Particles: Grace Drag Model
7.8.1.2. Interphase Drag for the Mixture Model
7.8.2. Lift Force
7.8.3. Virtual Mass Force
7.8.4. Wall Lubrication Force
7.8.5. Interphase Turbulent Dispersion Force
7.8.5.1. Favre Averaged Drag Model
7.8.5.2. Lopez de Bertodano Model
7.9. Solid Particle Collision Models
7.9.1. Solid Pressure Force Model
7.9.2. Maximum Packing
7.9.3. Kinetic Theory Models
7.10. Interphase Heat Transfer
7.10.1. Inhomogeneous Interphase Heat Transfer Models
7.10.1.1. Particle Model Correlations for Overall Heat Transfer Coefficient
7.10.1.2. Mixture Model Correlations for Overall Heat Transfer Coefficient
7.10.1.3. Two Resistance Model for Fluid Specific Heat Transfer Coefficients
7.10.2. Homogeneous Heat Transfer in Multiphase Flow
7.11. Polydispersed, Multiple Size Group (MUSIG) Model
7.11.1. Setting up a Polydispersed (MUSIG or IMUSIG) Simulation
7.11.1.1. Creating a Polydispersed (MUSIG) Fluid
7.11.1.2. Boundary Conditions
7.11.1.3. Initial Conditions
7.11.1.4. Sources
7.11.1.5. Postprocessing Variables
7.11.2. MUSIG Modeling Advice
7.12. Turbulence Modeling in Multiphase Flow
7.12.1. Phase-Dependent Turbulence Models
7.12.1.1. Algebraic Models
7.12.1.2. Two Equation Models
7.12.1.3. Reynolds Stress Models
7.12.2. Homogeneous Turbulence in Inhomogeneous Flow
7.12.3. Enhanced Turbulence Production Models
7.12.4. Turbulence in Homogeneous Multiphase Flow
7.13. Additional Variables in Multiphase Flow
7.13.1. Additional Variable Interphase Transfer Models
7.13.1.1. Particle Model Correlations
7.13.1.1.1. Ranz-Marshall Correlation
7.13.1.1.2. Hughmark Correlation
7.13.1.1.3. Sherwood Number
7.13.1.1.4. Additional Variable Transfer Coefficient
7.13.1.1.5. Interface Flux
7.13.1.2. Mixture Model Correlations
7.13.2. Homogeneous Additional Variables in Multiphase Flow
7.14. Sources in Multiphase Flow
7.14.1. Fluid-Specific Sources
7.14.2. Bulk Sources
7.15. Interphase Mass Transfer
7.15.1. Double Precision Solver
7.15.2. User Specified Mass Transfer
7.15.3. Thermal Phase Change Model
7.15.3.1. Saturation Temperature
7.15.3.2. Wall Boiling Model
7.15.3.2.1. RPI Model
7.15.3.2.2. Using a Wall Boiling Model
7.15.3.3. Latent Heat
7.15.3.4. Heat Transfer Models
7.15.3.5. Interphase Heat Transfer Correlations
7.15.3.6. Modeling Advice
7.15.3.6.1. Saturated Vapor Bubbles in Subcooled or Superheated Liquid
7.15.3.6.2. Subcooled or Superheated Droplets in Saturated Vapor
7.15.3.6.3. Superheated Vapor Bubbles in Liquid
7.15.3.6.4. Thermal Energy and Total Energy Models
7.15.4. Cavitation Model
7.15.4.1. Rayleigh Plesset Model
7.15.4.2. User Defined Cavitation Models
7.15.5. Interphase Species Mass Transfer
7.15.5.1. Component Pairs
7.15.5.2. Two Resistance Model
7.15.5.3. Single Resistance Model
7.15.5.4. Interfacial Equilibrium Models
7.15.5.4.1. Liquid Evaporation (Raoult’s Law)
7.15.5.4.2. Gas Absorption / Dissolution (Henry’s Law)
7.15.5.4.3. Other Situations
7.15.5.5. Species Mass Transfer Coefficients
7.15.5.6. Modeling Advice
7.15.5.6.1. Liquid Evaporation
7.15.5.6.2. Gas Dissolution
7.15.5.6.3. Mixture Properties
7.15.5.6.4. Current Limitations
7.15.6. Droplet Condensation Model
7.16. Boundary Conditions in Multiphase Flow
7.16.1. Wall Boundaries in Multiphase
7.16.1.1. Bulk Wall Boundary Conditions
7.16.1.1.1. Area Contact Model
7.16.1.2. Fluid Dependent Wall Boundary Conditions
7.16.1.3. Wall Deposition
7.16.2. Mass Flow Inlet
7.16.3. Mass Flow Outlet
7.17. Modeling Advice for Multiphase Flow
7.17.1. Turbulence Models
7.17.2. Minimum Volume Fraction Setting
7.17.3. Buoyancy
7.17.4. Initial Conditions
7.17.5. Timestepping
7.17.6. Convergence
7.17.7. Transient Simulations
7.18. Free Surface Flow
7.18.1. Interface Compression Level
7.18.2. Supercritical and Subcritical Flow
7.18.3. Multiphase Model Selection
7.18.4. Surface Tension
7.18.4.1. Background
7.18.4.2. Discretization Options
7.18.4.2.1. Volume Fraction Smoothing Type
7.18.4.2.2. Curvature Under-Relaxation Factor
7.18.4.3. Initial Conditions
7.18.4.4. Wall Adhesion
7.18.5. Modeling Advice for Free Surface Flow
7.18.5.1. Domains
7.18.5.2. Turbulence Model
7.18.5.3. Boundary Conditions
7.18.5.3.1. Pressure Reference
7.18.5.3.2. Outlets
7.18.5.4. Initial Conditions
7.18.5.5. Timestep
7.18.5.6. Mesh Adaption
7.18.5.7. Body Forces
7.18.5.8. Convergence
7.18.5.9. Parallel
7.19. Algebraic Slip Model (ASM)
7.19.1. Algebraic Slip Model Specification
7.19.1.1. Fluid Models
7.19.1.2. Wall Deposition
7.19.1.3. Limitations
7.20. Multiphase Flow Restrictions
8. Particle Transport Modeling
8.1. Model Validity
8.2. Particle Transport Versus Eulerian-Eulerian Multiphase
8.3. Forces Acting on the Particles
8.3.1. Drag Force
8.3.2. Reference Frame Rotational Forces
8.3.3. Buoyancy Force
8.4. Creating Particle Materials
8.5. Particle Domain Options
8.5.1. Basic Settings
8.5.1.1. Particle Morphology Options
8.5.2. Fluid Models
8.5.2.1. Multiphase Reactions
8.5.2.2. Buoyancy for Particles
8.5.2.3. Turbulence for Particles
8.5.2.4. Heat Transfer for Particles
8.5.2.5. Radiation for Particles
8.5.3. Fluid Specific Models
8.5.3.1. Particle Diameter Distribution
8.5.3.1.1. Specified Diameter
8.5.3.1.2. Uniform in Diameter by Number
8.5.3.1.3. Uniform in Diameter by Mass
8.5.3.1.4. Normal in Diameter by Number
8.5.3.1.5. Normal in Diameter by Mass
8.5.3.1.6. Rosin Rammler
8.5.3.1.7. Nukiyama Tanasawa
8.5.3.1.8. Discrete Diameter Distribution
8.5.3.2. Particle Shape Factors
8.5.3.3. Particle Diameter Change Due to Swelling
8.5.3.4. Heat Transfer
8.5.3.5. Erosion
8.5.3.5.1. Finnie
8.5.3.5.2. Tabakoff
8.5.3.5.3. User Defined
8.5.3.6. Particle-Rough Wall Model (Virtual Wall Model)
8.5.3.6.1. Sommerfeld-Frank Model
8.5.3.7. Particle Breakup Model
8.5.3.8. Particle Collision Model
8.5.3.8.1. Requirements for the Applicability of Particle-Particle Collision Model
8.5.3.9. Fluid Buoyancy Model
8.5.4. Fluid Pairs
8.5.4.1. Particle Fluid Pair Coupling Options
8.5.4.2. Drag Force for Particles
8.5.4.2.1. Particle User Source Example
8.5.4.2.2. Linearization Blend Factor
8.5.4.3. Particle User Source
8.5.4.4. Non-Drag Forces
8.5.4.4.1. Virtual Mass Force
8.5.4.4.2. Turbulent Dispersion Force
8.5.4.4.3. Pressure Gradient Force
8.5.4.5. Interphase Heat Transfer
8.5.4.5.1. Particle User Source
8.5.4.6. Interphase Radiation Transfer
8.5.4.6.1. Opaque
8.5.4.6.2. Blended Particle Emissivity
8.5.4.7. Mass Transfer
8.5.4.7.1. Ranz Marshall
8.5.4.7.2. Liquid Evaporation Model
8.5.4.7.3. Liquid Evaporation Model: Spray Dryer with Droplets Containing a Solid Substrate
8.5.4.7.4. Liquid Evaporation Model: Oil Evaporation/Combustion
8.5.4.7.5. Latent Heat
8.5.4.8. Particle User Sources
8.5.4.8.1. Particle User Source example
8.5.5. Particle Injection Regions
8.6. Particle Boundary Options and Behavior
8.6.1. Inlet/Opening Boundaries
8.6.1.1. Mass and Momentum
8.6.1.2. Particle Position
8.6.1.2.1. Uniform Injection
8.6.1.2.2. Uniform Injection within Annulus
8.6.1.2.3. Injection With Line Weighting
8.6.1.2.4. Injection With Point Weighting
8.6.1.2.5. Injection With Circular Weighting
8.6.1.2.6. Injection With User Defined Weighting
8.6.1.2.7. Injection at Face Centers
8.6.1.2.8. Injection at IP Face Centers
8.6.1.2.9. Number of Positions
8.6.1.2.10. Point Data Format
8.6.1.3. Particle Locations
8.6.1.4. Particle Diameter Distribution
8.6.1.5. Particle Mass Flow Rate
8.6.1.6. Heat Transfer
8.6.1.7. Component Details
8.6.1.8. Particle Actions at Inlets and Openings
8.6.2. Outlet Boundaries
8.6.2.1. Particle Actions at Outlets
8.6.3. Wall Boundaries
8.6.3.1. Wall Interaction
8.6.3.1.1. Standard Particle-Wall Interaction
8.6.3.1.1.1. Restitution Coefficients for Particles
8.6.3.1.2. Wall Film Modeling
8.6.3.1.2.1. User Defined Wall Film Modeling
8.6.3.1.3. User Defined Particle-Wall Interaction
8.6.3.2. Erosion Model
8.6.3.3. Particle-Rough Wall Model (Virtual Wall Model)
8.6.3.4. Particle Breakup
8.6.3.5. Mass Flow Absorption
8.6.3.6. Mass and Momentum
8.6.3.7. Particle Impact Angle
8.6.3.8. Particle Position
8.6.3.9. Particle Diameter Distribution
8.6.3.10. Particle Mass Flow Rate
8.6.4. Symmetry Plane Boundaries
8.6.5. Interface Boundaries
8.6.6. Domain Interfaces
8.6.6.1. Fluid-Fluid
8.6.6.1.1. Frame Change Option = None
8.6.6.1.2. Frame Change Option = Frozen Rotor
8.6.6.1.3. Frame Change Option = Stage (Mixing-Plane)
8.6.6.1.4. Frame Change Option = Transient Rotor Stator
8.6.6.2. Periodic Connections
8.7. Subdomains
8.8. Particle Injection Regions
8.8.1. Sphere
8.8.2. Cone
8.8.2.1. Injection Velocity
8.8.2.2. An Example of a Point Cone
8.8.2.3. An Example of a Point Cone Using the Dispersion Angle
8.8.2.4. An Example of a Hollow Cone using the Dispersion Angle
8.8.3. Cone with Primary Breakup
8.8.4. User Defined Injection Regions
8.9. Particle Output Control
8.9.1. Transient Particle Diagnostics
8.9.1.1. User Diagnostics Routine
8.9.1.1.1. Example User Routine: CCL
8.9.1.1.2. Example User Routine: Mainline Routine
8.9.1.1.3. Example User Routine: Subroutine
8.9.1.1.4. Example: Complete CCL
8.9.1.2. Particle Track Output
8.9.2. List of Particle Variables
8.10. Particle Solver Control
8.10.1. Particle Coupling Control
8.10.1.1. First Iteration for Particle Calculation
8.10.1.2. Iteration Frequency
8.10.1.3. Particle Source Change Target
8.10.2. Particle Under-Relaxation Factors
8.10.2.1. Under-Relaxation Factor for Velocity, Energy, and Mass
8.10.2.2. Under-Relaxation Factor for First Particle Integration
8.10.2.3. Under-Relaxation at Time Step Start
8.10.3. Particle Integration
8.10.3.1. Number of Integration Steps Per Element
8.10.3.2. Maximum Particle Integration Time Step
8.10.3.3. Chemistry Time Step Multiplier
8.10.4. Particle Termination Control
8.10.4.1. Maximum Tracking Time
8.10.4.2. Maximum Tracking Distance
8.10.4.3. Maximum Number of Integration Steps
8.10.4.4. Minimum Diameter
8.10.4.5. Minimum Total Mass
8.10.4.6. Mass Fraction Limits
8.10.5. Particle Ignition
8.10.6. Particle Source Smoothing
8.10.7. Vertex Variable Smoothing
8.10.8. Particle Source Control
8.10.8.1. Particle Heat Source Bounding
8.10.8.2. Particle Momentum Source Bounding
8.10.8.3. Linearization of Particle Mass Sources
8.10.8.3.1. Simple Mass Transfer Model
8.10.8.3.2. Liquid Evaporation Model
8.10.8.3.2.1. Droplet Temperature Below Boiling Point
8.10.8.3.2.2. Droplet Temperature Above Boiling Point
8.10.8.4. Particle Source Control Usage Notes
8.11. Multiphase Reactions and Combustion
8.11.1. Specification of a Binary Mixture
8.11.2. Reactants/Products
8.11.2.1. Example
8.11.3. Multiphase Reactions
8.11.3.1. Mass Arrhenius
8.11.3.2. Field Char Oxidation Model
8.11.3.3. Gibb Char Oxidation Model
8.11.3.4. Particle User Routine
8.11.3.5. Heat Release/Heat Release Distribution
8.11.4. Hydrocarbon Fuel Model Setup
8.11.4.1. Setup using Library Template (Recommended)
8.11.4.2. Set Up Manually (Experts)
8.11.4.3. Using Generic Multiphase Reactions Setup
8.12. Restrictions for Particle Transport
8.13. Restrictions for Particle Materials
8.14. Convergence Control for Particle Transport
8.15. Expert Parameters for Particle Tracking
8.16. Particle Diagnostics
8.17. Integrated Particle Sources for the Coupled Continuous Phase
8.18. Transient Simulations: What is Different for Particles?
9. Combustion Modeling
9.1. Reaction Models
9.1.1. Naming Convention for Reaction Schemes
9.1.2. Reaction Rate Types
9.1.2.1. Arrhenius
9.1.2.2. Arrhenius with Temperature PDF
9.1.2.3. Expression
9.1.2.4. Equilibrium
9.2. Using Combustion Models
9.2.1. Which Model is the Most Appropriate?
9.3. Eddy Dissipation Model
9.3.1. Fluid Models
9.3.1.1. Chemical Time Scale
9.3.1.2. Extinction Temperature
9.3.1.3. Maximum Flame Temperature
9.3.1.4. Mixing Rate Limit
9.3.1.5. Eddy Dissipation Model Coefficient A/B
9.3.1.6. Component Details
9.3.2. Initialization
9.3.3. Solver Parameters
9.4. Finite Rate Chemistry Model
9.4.1. Fluid Models
9.4.1.1. Chemical Time Scale
9.4.1.2. Extinction Temperature
9.4.1.3. Component Details
9.4.2. Initialization
9.4.3. Solver Parameters
9.5. Combined EDM/Finite Rate Chemistry Model
9.5.1. Fluid Models
9.5.1.1. Chemical Time Scale
9.5.1.2. Extinction Temperature
9.5.1.3. Component Details
9.5.2. Initialization
9.5.3. Solver Parameters
9.6. Reaction-Step Specific Combustion Model Control
9.7. Laminar Flamelet with PDF Model
9.7.1. Fluid Models
9.7.1.1. Component Details
9.7.2. Boundary Settings
9.7.2.1. Fuel
9.7.2.2. Oxidizer
9.7.2.3. Mixture Fraction
9.7.2.4. Mixture Fraction Mean and Variance
9.7.3. Initialization
9.7.4. Solver Parameters
9.8. Burning Velocity Model (Premixed or Partially Premixed)
9.8.1. Fluid Models
9.8.1.1. Component Details
9.8.2. Turbulent Burning Velocity
9.8.2.1. Value
9.8.2.2. Zimont Correlation
9.8.2.3. Peters Correlation
9.8.2.4. Mueller Correlation
9.8.3. Spark Ignition Model
9.8.3.1. Spark Kernel
9.8.3.2. Ignition Time
9.8.3.3. Spark Energy
9.8.4. Boundary Settings
9.8.4.1. Fuel
9.8.4.2. Oxidizer
9.8.4.3. Mixture Fraction
9.8.4.4. Mixture Fraction Mean and Variance
9.8.4.5. Reaction Progress
9.8.5. Initialization
9.8.5.1. Reaction Progress
9.8.6. Solver Parameters
9.8.7. Other Parameters
9.9. Extended Coherent Flame Model (ECFM)
9.9.1. Fluid Models
9.9.1.1. Laminar Flame Thickness
9.9.1.2. Component Details
9.9.2. Spark Ignition Model
9.9.2.1. Spark Kernel
9.9.2.2. Ignition Time
9.9.2.3. Spark Energy
9.9.3. Boundary Settings
9.9.3.1. Mixture
9.9.3.2. Reaction Progress
9.9.3.3. Flame Surface Density
9.9.4. Initialization
9.9.4.1. Mixture
9.9.4.2. Reaction Progress
9.9.4.3. Flame Surface Density
9.9.5. Solver Parameters
9.9.6. Other Parameters
9.10. Residual Material Model
9.10.1. Fluid Models
9.10.1.1. Reinitialization
9.10.2. Laminar Burning Velocity
9.10.3. Boundary Settings
9.10.4. Initialization
9.10.5. Other Parameters
9.11. Flamelet Libraries
9.11.1. Loading Flamelet Libraries
9.11.2. Flamelet Library (FLL) File Format
9.11.2.1. Flamelet Library (FLL) File Contents
9.11.2.2. Flamelet Library (FLL) File Format
9.11.2.2.1. Detailed FLL File Format
9.11.2.2.1.1. Comment Section
9.11.2.2.1.2. Header
9.11.2.2.1.3. Unburnt Flamelet
9.11.2.2.1.4. Burnt Flamelet Solution
9.11.2.2.2. Example FLL File
9.11.3. Stoichiometric Mixture Fraction
9.11.3.1. Value
9.11.3.2. Reactants
9.11.3.3. Automatic
9.11.4. Laminar Burning Velocity
9.11.4.1. Value
9.11.4.2. Metghalchi and Keck
9.11.4.3. Equivalence Ratio Correlation
9.11.4.3.1. Reference Burning Velocity
9.11.4.3.2. Flammability Limits
9.11.4.3.3. Preheat Temperature Dependency
9.11.4.3.4. Pressure Dependency
9.11.4.3.5. Residual Material Dependency
9.12. Autoignition Model
9.12.1. Ignition Delay Time
9.12.2. Customize Knock Reaction Rate
9.13. NO Model
9.13.1. Introduction to the NO Model
9.13.1.1. NO Model with Eddy Dissipation / Finite Rate Chemistry / Combined Model
9.13.1.2. NO Model with Flamelet Model
9.13.1.3. NO Model for Coal Combustion / Hydrocarbon Fuel Model
9.13.2. Fluid Models
9.13.2.1. Component Details
9.13.2.2. Boundary Conditions
9.13.3. Initialization
9.13.4. Solver Parameters
9.14. Chemistry Postprocessing
9.14.1. Fluid Models
9.14.1.1. Chemistry Postprocessing
9.14.1.2. Materials List
9.14.1.3. Reactions List
9.14.2. Boundary and Initial Conditions
9.14.3. Solver Parameters
9.15. Soot Model
9.15.1. Fluid Models
9.15.1.1. Soot Model
9.15.1.2. Fuel Material
9.15.1.3. Soot Material
9.15.1.4. Fuel Consumption Reaction
9.15.1.5. Fuel Carbon Mass Fraction
9.15.1.6. Soot Particle Mean Diameter
9.15.2. Boundary Settings
9.15.2.1. Mass Concentration and Nuclei Concentration
9.15.2.2. Mass Fraction and Specific Nuclei Specific Concentration
9.15.3. Initialization
9.16. Phasic Combustion
9.17. General Advice for Modeling Combusting Flows in CFX
9.17.1. General Procedure for Running Simulations
9.17.2. Advantages and Disadvantages of Multistep Reaction Mechanisms
9.17.3. Tips for Improving Convergence
9.17.4. Advanced Combustion Controls
10. Radiation Modeling
10.1. Comparison of the Radiation Models
10.2. Terminology
10.2.1. Absorptivity
10.2.2. Diffuse
10.2.3. Gray
10.2.4. Opaque
10.2.5. Reflectivity
10.2.6. Spectral
10.2.7. Transmissivity
10.3. Material Properties for Radiation
10.4. Rosseland Model
10.4.1. Fluid Models
10.4.1.1. Include Boundary Temperature Slip
10.4.1.2. Spectral Model
10.4.1.3. Scattering Model
10.4.2. Initial Conditions
10.4.3. Solver Control
10.5. The P1 Model
10.5.1. Fluid Models
10.5.1.1. Spectral Model
10.5.1.2. Scattering Model
10.5.2. Initial Conditions
10.5.3. Solver Control
10.6. The Discrete Transfer Model
10.6.1. Fluid Models
10.6.1.1. Number of Rays
10.6.1.2. Transfer Mode
10.6.1.3. Spectral Model
10.6.1.4. Scattering Model
10.6.2. Initial Conditions
10.6.3. Solver Control
10.7. The Monte Carlo Model
10.7.1. Fluid Models
10.7.1.1. Number of Histories
10.7.1.2. Transfer Mode
10.7.1.3. Spectral Model
10.7.1.4. Scattering Model
10.7.2. Initial Conditions
10.7.3. Solver Control
10.8. General Radiation Considerations
10.8.1. Domain Considerations
10.8.2. Domain Interface Considerations
10.8.3. Boundary Details
10.8.3.1. External Blackbody Temperature
10.8.3.2. Local Temperature
10.8.3.3. Radiation Intensity
10.8.3.4. Radiative Heat Flux
10.8.3.5. Emissivity
10.8.3.6. Diffuse Fraction
10.8.4. Sources
10.8.4.1. Directional Radiation Source
10.8.4.2. Isotropic Radiation Source
10.8.4.3. Directional Radiation Flux
10.8.4.4. Combining Radiation Sources
10.8.4.5. Isotropic Radiation Flux
10.8.5. Thermal Radiation Control
10.8.5.1. Iteration Interval
10.8.5.2. Diagnostic Output Level
10.8.5.3. Ray Reflection Control
10.8.5.4. Coarsening Control
10.8.5.4.1. Target Coarsening Rate
10.8.5.4.2. Minimum Blocking Factor
10.8.5.4.3. Maximum Blocking Factor
10.8.5.4.4. Small Coarse Grid Size
10.8.5.4.5. Diagnostic Output Level
10.8.5.5. Ray Tracing Control
10.8.5.5.1. Iteration Interval
10.8.5.5.2. Maximum Buffer Size
10.8.5.5.3. Maximum Number of Track Segments
10.8.5.5.4. Maximum Number of Iterations
10.8.5.5.5. Iteration Convergence Criterion
10.8.5.5.6. Ray Reflection Threshold
10.8.5.5.7. File Path
10.8.6. Spectral Model
10.8.6.1. Gray
10.8.6.2. Multiband
10.8.6.3. Multigray/Weighted Sum of Gray Gases
10.8.6.4. When is a Non-Gray Spectral Model Appropriate?
10.8.7. Scattering Model
10.8.7.1. Option = None
10.8.7.2. Option = Isotropic
10.8.7.3. Option = Linear Anisotropy
10.8.8. Radiometers
11. Rigid Body Modeling
11.1. Introduction to Rigid Body Modeling
11.2. Rigid Body Motion
11.3. Modeling a Rigid Body
11.3.1. Modeling a Rigid Body as a Collection of 2D Regions
11.3.2. Modeling a Rigid Body using an Immersed Solid
11.4. CEL Access of the Rigid Body State Variables
11.5. Monitor Plots related to Rigid Bodies
11.6. Solver Control of Rigid Bodies
11.7. Limitations to using Rigid Bodies
12. Real Fluid Properties
12.1. Setting up a Dry Real Gas Simulation
12.1.1. Using a Real Gas Equation of State
12.1.1.1. Redlich Kwong Dry Steam
12.1.1.2. Redlich Kwong Dry Refrigerants
12.1.1.3. Redlich Kwong Dry Hydrocarbons
12.1.1.4. Dry Redlich Kwong
12.1.2. Metastable States and Saturation Curve Clipping
12.1.3. Additional Comments
12.1.4. Using the IAPWS Equation of State
12.1.5. Using Real Gas Property (RGP) Tables
12.1.5.1. Loading .rgp files
12.1.5.2. Comments on Pressure and Temperature Ranges
12.1.5.3. Saturation Curve Clipping
12.1.6. Using a General Set-up (CEL or User Fortran)
12.1.6.1. Saturation Curve Clipping
12.2. Table Interpolation and Saturation Curve Clipping
12.2.1. Table Interpolation
12.2.2. Table Inversion
12.3. Equilibrium Phase Change Model
12.4. Setting up an Equilibrium Phase Change Simulation
12.4.1. Using a Real Gas Equation of State
12.4.1.1. Redlich Kwong Wet Steam
12.4.1.2. Redlich Kwong Wet Refrigerants
12.4.1.3. Redlich Kwong Wet Hydrocarbons
12.4.1.4. Wet Redlich Kwong
12.4.1.5. Creating a Liquid Phase Material
12.4.1.6. Creating the Homogeneous Binary Mixture
12.4.2. Using Real Gas Property (.rgp) table files
12.4.2.1. Loading an .rgp file
12.4.2.2. Creating the Homogeneous Binary Mixture
12.4.3. Using a General Set-up
12.4.3.1. Constants or Expressions
12.4.3.2. Antoine Equation
12.4.4. CFX-Pre Domain Models Set-up
12.5. Important Considerations
12.5.1. Properties
12.5.2. Inlet Boundary Conditions
12.6. Real Gas Property (RGP) File Contents
12.6.1. Superheat Region
12.6.2. Saturated Region
12.7. Real Gas Property (RGP) File Format
12.7.1. Organization of an .rgp File
12.7.1.1. Detailed .rgp File Format
12.7.1.2. Example .rgp File
12.8. Parameters in the .rgp File Controlling the Real Gas Model
12.8.1. REAL_GAS_MODEL
12.8.2. P_CRITICAL, T_CRITICAL
12.8.3. UNITS
12.8.4. MIN_PROPERTY_T, MAX_PROPERTY_T, MIN_PROPERTY_P and MAX_PROPERTY_P
12.8.5. MOLECULAR_VISCOSITY, MOLECULAR_CONDUCTIVITY
12.8.6. GAS_CONSTANT
12.8.7. TMIN_SATURATION, TMAX_SATURATION
12.8.8. P_TRIPLE, T_TRIPLE
12.8.9. SUPERCOOLING
13. Operating Maps and Operating Point Cases
13.1. Defining an Operating Point Case
13.2. Limitations
13.3. Running an Operating Point Case
13.4. Post-processing an Operating Point Case
14. Coupling CFX to an External Solver
14.1. Coupling CFX to an External Solver: System Coupling Simulations
14.1.1. Supported Capabilities and Limitations
14.1.2. Variables Available for System Coupling
14.1.2.1. Wall Force Data transferred from CFX System to System Coupling System
14.1.2.2. Displacement transferred from System Coupling System to CFX System
14.1.2.3. Thermal Data exchange between CFX and System Coupling
14.1.3. System Coupling Related Settings in CFX
14.1.4. Restarting CFX Analyses as Part of System Coupling
14.1.4.1. Generating CFX Restart Files
14.1.4.2. Specify a Restart Point in CFX
14.1.4.3. Making Changes in CFX Before Restarting
14.1.4.4. Recovering the CFX Restart Point after a Workbench Crash
14.1.4.5. Restarting from the Beginning of the Coupled Analysis in Workbench
14.1.5. Initializing a Coupled CFX Analysis from an Independent CFX Analysis
14.1.6. Running CFX as a Participant from System Coupling's GUI or CLI
14.1.7. Product Licensing Considerations when using System Coupling
14.2. Coupling CFX to an External Solver: Functional Mock-up Interface (FMI) Co-simulation
14.2.1. Limitations of using CFX with FMI
14.2.2. Units of FMU Output Variables
14.3. Coupling CFX to an External Solver: GT-SUITE Coupling Simulations
14.3.1. Supported Capabilities and Limitations
14.3.2. GT-SUITE Coupling Related Settings in CFX
14.3.3. Setting up a CFX Simulation to use GT-SUITE
14.3.3.1. Initializing or Re-initializing a GT-SUITE Model
14.3.3.2. Editing a GT-SUITE Model
14.3.4. Restarting CFX Analyses as Part of GT-SUITE Coupling
15. Aerodynamic Noise Analysis
15.1. Overview of Aerodynamic Noise Analysis
15.1.1. Near Field Noise Prediction
15.1.2. Far Field Noise Prediction
15.2. Types of Noise Sources
15.2.1. Monopole Sources
15.2.2. Dipole and Rotating Dipole Sources
15.2.3. Quadrupole Sources
15.3. Noise Source Strength Estimation in CFX
15.3.1. Monopole Sources
15.3.1.1. Monopole Data in the CFX-Solver Manager
15.3.1.2. Exporting Surface Monopole Data
15.3.2. Dipole or Rotating Dipole Sources
15.3.2.1. Dipole Data in the CFX-Solver Manager
15.3.2.2. Exporting Surface Dipole Data
15.3.3. Important Boundary Results Export Notes
15.3.4. Quadrupole Sources
15.3.4.1. Exporting Acoustic Quadrupole Data
15.4. The CGNS Export Data Format
15.4.1. File Naming Conventions
15.4.1.1. Important Notes
15.4.2. CGNS File Structure
15.4.2.1. Common Nodes for Mesh and Solution Files
15.4.2.2. Mesh File Specific Nodes
15.4.2.3. Solution File Specific Nodes
16. Advice on Flow Modeling
16.1. Solving Problems with Ansys CFX
16.2. Modeling 2D Problems
16.3. Mesh Issues
16.3.1. Physical Modeling Errors: YPLUS and Mesh Resolution Near the Wall
16.3.2. Measures of Mesh Quality
16.3.2.1. Mesh Orthogonality
16.3.2.2. Mesh Expansion
16.3.2.3. Mesh Aspect Ratio
16.4. Timestep Selection
16.4.1. Steady-state Time Scale Control
16.4.1.1. Max. Iterations
16.4.1.2. Minimum Number of Iterations
16.4.1.3. Time Scale Control
16.4.1.3.1. Auto Timescale
16.4.1.3.1.1. Length Scale Option
16.4.1.3.1.2. Timescale Factor
16.4.1.3.1.3. Maximum Timescale
16.4.1.3.1.4. Controlling the Time Scale with the Command File Editor
16.4.1.3.2. Local Time Scale Factor
16.4.1.3.3. Physical Time Scale
16.4.1.4. Solid Time Scale Control
16.4.1.4.1. Solid Timescale Factor
16.4.1.5. Controlling the Timescale for Each Equation
16.4.2. Transient Timestep Control
16.4.2.1. Time Duration
16.4.2.2. Timesteps: Timesteps List
16.4.2.3. Timesteps: Timesteps for the Run List
16.4.2.4. Timesteps: Adaptive
16.4.2.5. Initial Time
16.4.2.6. Max. Iter. Per Step
16.4.2.7. Transient Scheme
16.4.2.7.1. First Order Backward Euler
16.4.2.7.2. Second Order Backward Euler
16.4.2.7.2.1. Timestep Initialization
16.4.2.7.3. High Resolution
16.4.2.7.4. Harmonic Balance
16.4.2.7.5. Bounded Harmonic Balance
16.4.2.7.6. None
16.5. Advection Scheme Selection
16.5.1. Upwind
16.5.2. High Resolution
16.5.3. Specified Blend Factor
16.5.4. Central Difference
16.5.5. Advection Scheme for Turbulence Equations
16.5.6. Advection Schemes for Multiphase Volume Fractions
16.5.7. Comparisons to CFX-TASCflow
16.6. Dynamic Model Control
16.6.1. Global Dynamic Model Control
16.6.2. Turbulence Control
16.6.3. Combustion Control
16.6.4. Hydro Control
16.6.5. Harmonic Balance Control
16.7. Pressure Level Information
16.8. Interpolation Scheme
16.8.1. Pressure Interpolation Type
16.8.2. Velocity Interpolation Type
16.8.3. Shape Function Option
16.9. Temperature Damping
16.9.1. Option
16.9.2. Temperature-Damping Limit
16.9.3. Under-Relaxation Factor
16.10. Monitoring and Obtaining Convergence
16.10.1. Residuals
16.10.1.1. Residual Type and Target Levels
16.10.1.1.1. RMS Residual Level
16.10.1.1.2. MAX Residual Level
16.10.2. Using Interrupt Control in Cases with Transient Convergence Behavior
16.10.3. Global Balances and Integrated Quantities
16.10.3.1. Positive and Negative Domain Source Totals
16.10.3.2. Conservation Target
16.10.4. Convergence Rate
16.10.5. Problems with Convergence
16.10.5.1. Start-up Problems
16.10.5.2. Later Problems
16.11. Solver Issues
16.11.1. Robustness and Accuracy
16.11.2. Linear Solver Failure
16.12. How CEL Interacts with the CFX-Solver
16.13. Best Practice Guides
17. Using the Solver in Parallel
17.1. Partitioning
17.1.1. Node-based and Element-based Partitioning
17.1.2. Multilevel Graph Partitioning Software - MeTiS
17.1.3. Recursive Coordinate Bisection
17.1.4. Optimized Recursive Coordinate Bisection
17.1.5. Simple Assignment
17.1.6. User Specified Direction
17.1.7. Directional Recursive Coordinate Bisection
17.1.8. Radial
17.1.9. Circumferential
17.2. Setup for Parallel Runs
17.3. Message Passing Interface (MPI) for Parallel
17.4. Advice on Using Ansys CFX in Parallel
17.4.1. Optimizing Mesh Partitioning
17.4.2. Optimizing the Parallel Run
17.4.3. Error Handling
17.4.3.1. Problems with Intel MPI
17.4.3.1.1. Semaphores and Shared-memory Segments
17.4.3.1.2. Typical Problems When You Run Out of Semaphores
17.4.3.1.3. Checking How Many Semaphores Are in Use, and by Whom
17.4.3.1.4. Deleting the Semaphores You Are Using
17.4.3.1.5. Shared-memory Segment Size Problems
17.4.3.1.6. Checking Semaphore ID and Shared Memory Segment Limits
17.4.3.1.6.1. Linux
17.4.3.1.7. Increasing the Maximum Number of Semaphores for Your System
17.4.3.1.8. Max Locked Memory
17.4.3.2. Problems with the Ansys CFX Executables
17.4.3.3. Problems with Ansys CFX Licenses
17.4.3.4. Windows Problems
17.4.3.5. Linux Problems
17.4.3.6. Convergence Problems
17.4.4. Measuring Parallel Performance
17.4.4.1. Wall Clock Performance
17.4.4.2. Memory Efficiency
17.4.4.3. Visualizing Mesh Partitions
18. Expert Control Parameters
18.1. When to Use Expert Control Parameters
18.2. Modifying Expert Control Parameters
18.3. CFX-Solver Expert Control Parameters
18.3.1. Discretization Parameters
18.3.2. Linear Solver Parameters
18.3.3. I/O Control Parameters
18.3.4. Convergence Control Parameters
18.3.5. Physical Model Parameters
18.3.6. Particle Tracking Parameters
18.3.7. Transient Blade Row Model Parameters
18.3.8. Run Control Parameters
18.3.9. Model Override Parameters
19. User Fortran
19.1. User CEL Functions and Routines
19.1.1. Structure of User CEL Functions
19.1.2. User CEL Function Units
19.2. User Junction Box Routines
19.2.1. Junction Box Routine Options and Parameters
19.2.2. Calling Junction Box Routines
19.2.3. Reading Data with the User Input Option
19.2.4. Writing Data with the User Output Option
19.2.5. Other Junction Box Location Options
19.2.6. Structure of the User Junction Box Routines
19.2.7. Which Call
19.3. Shared Libraries
19.3.1. Creating the Shared Libraries
19.3.2. Default Fortran Compilers and Compiler Options
19.4. User Parameters
19.4.1. Adding and Modifying User Parameters
19.4.2. Parameter Names
19.4.3. Parameter Values
19.4.4. Example of CCL File User Parameters
19.4.5. Looking up a String Value
19.4.6. String Value Example
19.4.7. Looking Up List Values
19.4.8. Real Value Example
19.4.9. Looking up Sizes of Lists and Strings
19.4.10. Real List Example
19.4.11. Printing Parameters
19.5. Utility Routines for User Functions
19.5.1. Introduction to Utility Routines for User Functions
19.5.2. Data Acquisition Routines
19.5.2.1. USER_GETVAR
19.5.2.1.1. Boundcon Operator
19.5.2.1.2. Variable Shape and Dimensions
19.5.2.2. USER_GET_GVAR
19.5.2.2.1. USER_GET_GVAR with Multiphase Flow
19.5.2.3. USER_CALC_INFO
19.5.2.4. USER_GET_MESH_INFO
19.5.2.4.1. Global Mesh Information: CZONE = ‘ ‘, LOCALE = ‘ ‘
19.5.2.4.2. Zonal Information: CZONE = ‘ZNm’, LOCALE = ‘ ‘
19.5.2.4.3. Boundary Condition Patch Information: CZONE = ‘ZNm’, LOCALE = ‘BCPn‘
19.5.2.4.3.1. Face Set Information: CZONE = ‘ZNm’, LOCALE = ‘FCSn‘
19.5.2.4.3.2. Element Set or Element Group Information: CZONE = ‘ZNm’, LOCALE = ‘ELSn‘ or ‘IELGn‘ or ‘BELGn‘
19.5.2.5. USER_GET_MESHDATA
19.5.2.6. USER_GET_PHYS_INFO
19.5.2.6.1. Zonal Information: CZONE = ‘ZNm’, CPHASE = ‘ ‘
19.5.2.6.2. Phase Information: CZONE = ‘ZNm’, CPHASE = ‘FLm‘ or ‘SLm’
19.5.2.7. USER_GET_TRANS_INFO
19.5.2.8. USER_ASSEMBLE_INFO
19.5.2.9. GET_PARALLEL_INFO
19.5.2.10. CAL_MESHMAP
19.5.3. Name Conversions
19.5.3.1. CONVERT_NAME_U2S
19.5.3.2. CONVERT_NAME_S2U
19.5.3.3. VAR_ALIAS
19.5.3.4. LOCALE_ALIAS
19.5.3.5. CONVERT_USER_NAMES
19.5.3.6. GET_PHASE_FROM_VAR
19.5.3.7. PARSMP
19.5.4. Character Handling
19.5.4.1. CFROMD
19.5.4.2. CFROMI
19.5.4.3. CFROMR
19.5.4.4. DFROMC
19.5.4.5. IFROMC
19.5.4.6. RFROMC
19.5.4.7. LENACT
19.5.4.8. EDIT
19.5.4.9. IOPNAM
19.5.4.10. CCATI
19.5.5. Output Routines
19.5.5.1. MESAGE
19.5.5.2. ERRMSG
19.6. CFX Memory Management System (MMS)
19.6.1. Introduction to the Memory Management System
19.6.2. Error Conventions
19.6.3. Stack Pointers
19.6.4. Subroutines
19.6.4.1. Directories
19.6.4.1.1. MAKDIR
19.6.4.1.2. DELDIR
19.6.4.1.3. CHGDIR
19.6.4.1.4. CHMDIR
19.6.4.1.5. PSHDIR
19.6.4.1.6. PSHDRH
19.6.4.1.7. POPDIR
19.6.4.1.8. LISDAT
19.6.4.1.9. PUTDIR
19.6.4.1.10. FNDFIL
19.6.4.2. Data Areas
19.6.4.2.1. MAKDAT
19.6.4.2.2. MAKVEC
19.6.4.2.3. GRBSTK
19.6.4.2.4. SQZDAT
19.6.4.2.5. RESIZE
19.6.4.2.6. DELDAT
19.6.4.2.7. LOCDAT
19.6.4.2.8. INFDAT
19.6.4.3. Renaming And Linking
19.6.4.3.1. RENAM
19.6.4.3.2. MAKLNK
19.6.4.3.3. DELLNK
19.6.4.4. Copying
19.6.4.4.1. COPDAT
19.6.4.4.2. COPDIR
19.6.4.5. Setting and Reading Individual Values
19.6.4.5.1. POKECA
19.6.4.5.2. POKECS
19.6.4.5.3. POKED
19.6.4.5.4. POKEI
19.6.4.5.5. POKEL
19.6.4.5.6. POKER
19.6.4.5.7. PEEKCA
19.6.4.5.8. PEEKCS
19.6.4.5.9. PEEKD
19.6.4.5.10. PEEKI
19.6.4.5.11. PEEKL
19.6.4.5.12. PEEKR
19.6.4.6. Name lists
19.6.4.6.1. NAMLST
19.6.4.7. Memory Management Statistics
19.6.4.7.1. GETMMS
19.6.4.7.2. WSTAT
19.7. User Fortran in Ansys Workbench
19.8. User CEL Examples
19.8.1. User CEL Example 1: User Defined Momentum Source
19.8.1.1. Problem Setup
19.8.1.2. Creating the User CEL Function
19.8.1.3. User Fortran Routine
19.8.2. User CEL Example 2: Using Gradients for an Additional Variable Source
19.8.2.1. Problem Setup
19.8.2.1.1. Creating the Additional Variables
19.8.2.1.2. Creating the Domain
19.8.2.1.3. Creating the User CEL Routine and Function
19.8.2.1.4. Defining the Source Term
19.8.2.2. User Fortran Routine
19.8.3. User CEL Example 3: Integrated Quantity Boundary Conditions
19.8.3.1. Problem Setup
19.8.3.1.1. Creating the User Function
19.8.3.2. User Fortran Routine
19.9. User Junction Box Examples
19.9.1. Junction Box Example 1: Profile Boundary Conditions
19.9.1.1. Problem Setup
19.9.1.1.1. Creating the Junction Box Routine and User CEL Function
19.9.1.1.2. Setting the Boundary Condition
19.9.1.1.3. Enabling the Junction Box Routine
19.9.1.2. User Fortran Junction Box Routines
19.9.2. Junction Box Example 2: Integrated Residence Time Distribution
19.9.2.1. Problem Setup
19.9.2.1.1. Creating the Additional Variables
19.9.2.1.2. Creating the Domains
19.9.2.1.3. Creating the Subdomains and Additional Variable Sources
19.9.2.1.4. Creating the Junction Box Routine
19.9.2.1.5. Enabling the Junction Box Routine
19.9.2.2. User Fortran Junction Box Routine
19.9.3. Junction Box Example 3: Timestep Control
19.9.4. Junction Box Example 4: Solver Control
19.9.5. Junction Box Example 5: Transient Information
19.10. Using CFX-4 Routines in CFX
19.11. State Point Evaluation
19.11.1. General Usage Notes
19.11.2. Supported Independent Thermodynamic Input Properties
19.11.3. Supported Thermodynamic Output Properties
19.11.4. Input and Output Property Name Format
19.11.4.1. Pure Substance Example
19.11.4.2. Mixture Example
19.11.5. Supported Material Types
19.11.6. Error Checks
19.11.7. USER_STATEPT Example 1
19.11.8. USER_STATEPT Example 2
19.12. Calculating the Particle Drag Coefficient
19.12.1. USER_PARTICLE_INFO Routine