Phase inversion in a closed box
[Problem Description] Phase inversion in a closed box.pdf | |
File Size: | 1334 kb |
File Type: |
Test log
Software: ANSYS Fluent
Oil density: 900kg/m3; viscosity: 0.1kg/m-s
Water density: 1000kg/m3; viscosity: 0.005kg/m-s
Procedures
Mesh
1. Right-click the Mesh object and select Insert→Mapped Face Meshing . Click Geometry→Apply to confirm that the selected body is the correct geometry to mesh.
2. With the Mesh object selected, in the Details View, expand the Sizing specification. Set Max Face Size to 7.8431e-4, thereby limiting the elements to 7.8431e-4m×7.8431e-4m maximum extension.
3. Click Update .
Reference: http://uiuc-cse.github.io/me498cm-fa15/lessons/fluent/pipe-2d.html
Mark region
1. Adapt->Region. Select region by specifying points. Click 'Mark'. Don't close the window.
2. Mesh->Separate->Faces. Select 'Mark' under 'Options'. Select under 'Register' and 'Zones' and click 'Separate'. Now the zone of interest has been separated from the other domain.
Oil density: 900kg/m3; viscosity: 0.1kg/m-s
Water density: 1000kg/m3; viscosity: 0.005kg/m-s
Procedures
Mesh
1. Right-click the Mesh object and select Insert→Mapped Face Meshing . Click Geometry→Apply to confirm that the selected body is the correct geometry to mesh.
2. With the Mesh object selected, in the Details View, expand the Sizing specification. Set Max Face Size to 7.8431e-4, thereby limiting the elements to 7.8431e-4m×7.8431e-4m maximum extension.
3. Click Update .
Reference: http://uiuc-cse.github.io/me498cm-fa15/lessons/fluent/pipe-2d.html
Mark region
1. Adapt->Region. Select region by specifying points. Click 'Mark'. Don't close the window.
2. Mesh->Separate->Faces. Select 'Mark' under 'Options'. Select under 'Register' and 'Zones' and click 'Separate'. Now the zone of interest has been separated from the other domain.
1. Graduate change/diffusion of volume fraction. May be due to the low accuracy caused by large time step.
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Settings
-General: Pressure-Based; Absolute velocity formulation; Transient; Planar; Gravity set to -9.81m/s2 in y direction. -Model -Multiphase Model: Volume of Fluid; 2 Eulerian Phases; Level Set off; Volume Fraction Parameters Implicit Formulation and Cutoff at 1e-6; Implicit Body Force off; Sharp Interface Modeling with Interfacial Anti-Diffusion off; Phase Interaction: no mas transfer with surface tension force modeling on: surface tension coefficients 0.045n/m; Continuum surface force; Wall adhesion on; Jump adhesion off. -Viscous Model: Laminar. -Other models off. -Solution Methods Non-Iterative Time advancement. Fractional Step Scheme for Pressure-Velocity Coupling. Spatial Discretization -Gradient: Least Square Cell Based. -Pressure: PRESTO!. -Momentum: QUICK. -Volume Fraction: Compressive. Transient Formulation: First Order Implicit. Fixed Time Stepping Method Time step size: 0.01s Grid:256*256 Max Face Size=0.00078431372m |
1. Turbulent model gets stabilized faster than laminar model, due to the dissipation of kinetic energy with turbulent viscosity.
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Settings
-General: Pressure-Based; Absolute velocity formulation; Transient; Planar; Gravity set to -9.81m/s2 in y direction. -Model -Multiphase Model: Volume of Fluid; 2 Eulerian Phases; Level Set off; Volume Fraction Parameters Implicit Formulation and Cutoff at 1e-6; Implicit Body Force off; Sharp Interface Modeling with Interfacial Anti-Diffusion off; Phase Interaction: no mas transfer with surface tension force modeling on: surface tension coefficients 0.045n/m; Continuum surface force; Wall adhesion on; Jump adhesion off. -Viscous Model: k-epsilon (2 eqn); Standard model; Standard Wall Functions; Cmu=0.09; C1-Epsilon=1.44; C2-Epsilon=1.92; TKE Pr Number=1; Options all off. -Other models off. -Solution Methods Non-Iterative Time advancement. Fractional Step Scheme for Pressure-Velocity Coupling. Spatial Discretization -Gradient: Least Square Cell Based. -Pressure: PRESTO!. -Momentum: QUICK. -Volume Fraction: Compressive. -Transient Formulation: First Order Implicit. -Turbulent Kinetic Energy: First Order Upwind. -Specific Dissipation Rate: First Order Upwind. Fixed Time Stepping Method Time step size: 0.01s Grid:256*256 Max Face Size=0.00078431372m |
1. Second order implicit should provide higher accuracy compared with first order implicit transient formulation. However, the result shows that mass/volume is not conserved. The steady state water level should be at 3/4 of the box height since there should be no change in phase mass and volume.
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Settings
-General: Pressure-Based; Absolute velocity formulation; Transient; Planar; Gravity set to -9.81m/s2 in y direction. -Model -Multiphase Model: Volume of Fluid; 2 Eulerian Phases; Level Set off; Volume Fraction Parameters Implicit Formulation and Cutoff at 1e-6; Implicit Body Force off; Sharp Interface Modeling with Interfacial Anti-Diffusion off; Phase Interaction: no mas transfer with surface tension force modeling on: surface tension coefficients 0.045n/m; Continuum surface force; Wall adhesion on; Jump adhesion off. -Viscous Model: Laminar. -Other models off. -Solution Methods Non-Iterative Time advancement. Fractional Step Scheme for Pressure-Velocity Coupling. Spatial Discretization -Gradient: Least Square Cell Based. -Pressure: PRESTO!. -Momentum: QUICK. -Volume Fraction: Compressive. Transient Formulation: Second Order Implicit. Fixed Time Stepping Method Time step size: 0.01s Grid:256*256 Max Face Size=0.00078431372m |
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Settings
-General: Pressure-Based; Absolute velocity formulation; Transient; Planar; Gravity set to -9.81m/s2 in y direction. -Model -Multiphase Model: Volume of Fluid; 2 Eulerian Phases; Level Set off; Volume Fraction Parameters Implicit Formulation and Cutoff at 1e-6; Implicit Body Force off; Sharp Interface Modeling with Interfacial Anti-Diffusion off; Phase Interaction: no mas transfer with surface tension force modeling on: surface tension coefficients 0.045n/m; Continuum surface force; Wall adhesion on; Jump adhesion off. -Viscous Model: k-omega (2 eqn); Standard; Shear Flow Corrections on; Production Limiter on; Alpha*_inf=1; Alpha_inf=0.52; Beta*_inf=0.09; Beta_i=0.072; TKE Pr Number=2; SDR Pr Number=2; Production Limiter Clip Factor=10; Other options off. -Other models off. -Solution Methods Non-Iterative Time advancement. Fractional Step Scheme for Pressure-Velocity Coupling. Spatial Discretization -Gradient: Least Square Cell Based. -Pressure: PRESTO!. -Momentum: QUICK. -Volume Fraction: Compressive. -Turbulent Kinetic Energy: First Order Upwind. -Specific Dissipation Rate: First Order Upwind. Transient Formulation: First Order Implicit. Fixed Time Stepping Method Time step size: 0.01s Grid:256*256 Max Face Size=0.00078431372m |
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Settings
-General: Pressure-Based; Absolute velocity formulation; Transient; Planar; Gravity set to -9.81m/s2 in y direction. -Model -Multiphase Model: Volume of Fluid; 2 Eulerian Phases; Level Set off; Volume Fraction Parameters Explicit Formulation and Cutoff at 1e-6 Courant Number = 0.25; Implicit Body Force off; Sharp Interface Modeling with Interfacial Anti-Diffusion off; Phase Interaction: no mas transfer with surface tension force modeling on: surface tension coefficients 0.045n/m; Continuum surface force; Wall adhesion on; Jump adhesion off. -Viscous Model: Laminar. -Other models off. -Solution Methods Non-Iterative Time advancement. Fractional Step Scheme for Pressure-Velocity Coupling. Spatial Discretization -Gradient: Least Square Cell Based. -Pressure: PRESTO!. -Momentum: QUICK. -Volume Fraction: Compressive. Transient Formulation: First Order Implicit. Fixed Time Stepping Method Time step size: 0.01s Grid:256*256 Max Face Size=0.00078431372m |
1. Sharp transition from phase to phase. Higher accuracy compared with time step size of 0.01 s.
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Settings
-General: Pressure-Based; Absolute velocity formulation; Transient; Planar; Gravity set to -9.81m/s2 in y direction. -Model -Multiphase Model: Volume of Fluid; 2 Eulerian Phases; Level Set off; Volume Fraction Parameters Implicit Formulation and Cutoff at 1e-6; Implicit Body Force off; Sharp Interface Modeling with Interfacial Anti-Diffusion off; Phase Interaction: no mas transfer with surface tension force modeling on: surface tension coefficients 0.045n/m; Continuum surface force; Wall adhesion on; Jump adhesion off. -Viscous Model: Laminar. -Other models off. -Solution Methods Non-Iterative Time advancement. Fractional Step Scheme for Pressure-Velocity Coupling. Spatial Discretization -Gradient: Least Square Cell Based. -Pressure: PRESTO!. -Momentum: QUICK. -Volume Fraction: Compressive. Transient Formulation: First Order Implicit. Fixed Time Stepping Method Time step size: 0.001s Grid:256*256 Max Face Size=0.00078431372m |
1. Changing the grid from 256*256 to 129*129 does not affect the result much.
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Settings
-General: Pressure-Based; Absolute velocity formulation; Transient; Planar; Gravity set to -9.81m/s2 in y direction. -Model -Multiphase Model: Volume of Fluid; 2 Eulerian Phases; Level Set off; Volume Fraction Parameters Implicit Formulation and Cutoff at 1e-6; Implicit Body Force off; Sharp Interface Modeling with Interfacial Anti-Diffusion off; Phase Interaction: no mas transfer with surface tension force modeling on: surface tension coefficients 0.045n/m; Continuum surface force; Wall adhesion on; Jump adhesion off. -Viscous Model: Laminar. -Other models off. -Solution Methods Non-Iterative Time advancement. Fractional Step Scheme for Pressure-Velocity Coupling. Spatial Discretization -Gradient: Least Square Cell Based. -Pressure: PRESTO!. -Momentum: QUICK. -Volume Fraction: Compressive. Transient Formulation: First Order Implicit. Fixed Time Stepping Method Time step size: 0.01s Grid:129*129 Max Face Size=0.0015625m |
Reference
tut18.pdf | |
File Size: | 3154 kb |
File Type: |