8.3.1. Run Control¶
8.3.1.1. RUN_NAME¶
Data Type: CHARACTER
required
Name used to create output files. The name should generate legal file names after appending extensions. Ex: Given the input, RUN_NAME = “bub01”, MFIX will generate the output files: BUB01.LOG, BUB01.OUT, BUB01.RES, etc.
8.3.1.4. UNITS¶
Data Type: CHARACTER
required
Simulation input/output units.
Name |
Default? |
Description |
|---|---|---|
|
All input and output in CGS units (g, cm, s, cal). |
|
|
All input and output in SI units (kg, m, s, J). |
8.3.1.5. RUN_TYPE¶
Data Type: CHARACTER
required
Type of run.
Name |
Default? |
Description |
|---|---|---|
|
A new run. There should be no .RES, .SPx, .OUT, or .LOG files in the run directory. |
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|
Traditional restart. The run continues from the last time the .RES file was updated and new data is added to the SPx files. |
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|
Start a new run with initial conditions from a .RES file created from another run. No other data files (SPx) should be in the run directory. |
8.3.1.9. DT¶
Data Type: DOUBLE PRECISION
Initial time step size. If left undefined, a steady-state calculation is performed.
8.3.1.12. DT_FAC¶
Data Type: DOUBLE PRECISION
Factor for adjusting time step.
The value must be less than or equal to 1.0.
A value of 1.0 keeps the time step constant which may help overcome initial non-convergence.
8.3.1.13. PERSISTENT_MODE¶
Data Type: LOGICAL
Force a forward time-step if the maximum number of iterations, MAX_NIT, is reached. The forward time-step is only forced after reaching the minimum time-step, DT_MIN, for adjustable time-step simulations (DT_FAC /= 1). This option should be used with caution as unconverged time-steps may lead to poor simulation results and/or additional convergence issues.
Name |
Default? |
Description |
|---|---|---|
|
Force forward time-step when DT=DT_MIN and the maximum number of iterations are reached. |
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|
◉ |
Abort run when DT < DT_MIN. |
8.3.1.15. MOMENTUM_X_EQ(PHASE)¶
Data Type: LOGICAL
\(0 \le Phase \le 10\)
Flag to enable/disable solving the X-momentum equations.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Solve X-momentum equations. |
|
The X velocity initial conditions persist throughout the simulation. |
8.3.1.16. MOMENTUM_Y_EQ(PHASE)¶
Data Type: LOGICAL
\(0 \le Phase \le 10\)
Flag to enable/disable solving the Y-momentum equations.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Solve Y-momentum equations. |
|
The Y velocity initial conditions persist throughout the simulation. |
8.3.1.17. MOMENTUM_Z_EQ(PHASE)¶
Data Type: LOGICAL
\(0 \le Phase \le 10\)
Flag to enable/disable solving the Z-momentum equations.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Solve Z-momentum equations. |
|
The Z velocity initial conditions persist throughout the simulation. |
8.3.1.18. JACKSON¶
Data Type: LOGICAL
Flag to enable Jackson form of momentum equations. See Anderson and Jackson, (1967), IECF, 6(4), p.527.
Name |
Default? |
Description |
|---|---|---|
|
Solve Jackson form of momentum equations. |
|
|
◉ |
Default form. |
8.3.1.19. ISHII¶
Data Type: LOGICAL
Flag to enable Ishii form of momentum equations. See Ishii, (1975), Thermo-fluid dynamic theory of two-phase flow.
Name |
Default? |
Description |
|---|---|---|
|
Solve Ishii form of momentum equations. |
|
|
◉ |
Default form. |
8.3.1.20. ENERGY_EQ¶
Data Type: LOGICAL
Solve energy equations.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Solve energy equations. |
|
Do not solve energy equations. |
8.3.1.21. SPECIES_EQ(PHASE)¶
Data Type: LOGICAL
\(0 \le Phase \le 10\)
Solve species transport equations.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Solve species equations. |
|
Do not solve species equations. |
8.3.1.22. TURBULENCE_MODEL¶
Data Type: CHARACTER
Gas phase turbulence model. [“NONE”]
For K_EPSILON (K-epsilon turbulence model for single-phase flow):
Numerical parameters (like under-relaxation) are the same as the ones for SCALAR (index = 9).
All walls must be defined (NSW, FSW or PSW) in order to use standard wall functions. If a user does not specify a wall type, the simulation will not contain the typical turbulent profile in wall-bounded flows.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
No turbulence model. |
|
Turbulent length scale must be specified for the full domain using keyword IC_L_SCALE. |
|
|
K-epsilon turbulence model (for single-phase flow) using standard wall functions. |
8.3.1.23. MU_GMAX¶
Data Type: DOUBLE PRECISION
Maximum value of the turbulent viscosity of the fluid, which must be defined if any turbulence model is used. A value MU_GMAX =1.E+03 is recommended. (see calc_mu_g.f)
8.3.1.24. DRAG_TYPE¶
Data Type: CHARACTER
Available gas-solids drag models. Note: The extension _PCF following the specified drag model indicates that the polydisperse correction factor is available. This option is available for TFM solids only. For PCF details see:
Van der Hoef MA, Beetstra R, Kuipers JAM. (2005) Journal of Fluid Mechanics.528:233-254.
Beetstra, R., van der Hoef, M. A., Kuipers, J.A.M. (2007). AIChE Journal, 53:489-501.
Erratum (2007), AIChE Journal, Volume 53:3020
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Syamlal M, OBrien TJ (1988). International Journal of Multiphase Flow 14:473-481. Two additional parameters may be specified: DRAG_C1, DRAG_D1 |
|
Ding J, Gidaspow D (1990). AIChE Journal 36:523-538 |
|
|
Lathouwers D, Bellan J (2000). Proceedings of the 2000 U.S. DOE Hydrogen Program Review NREL/CP-570-28890. |
|
|
Wen CY, Yu YH (1966). Chemical Engineering Progress Symposium Series 62:100-111. |
|
|
Hill RJ, Koch DL, Ladd JC (2001). Journal of Fluid Mechanics, 448: 213-241. and 448:243-278. |
|
|
Beetstra, van der Hoef, Kuipers (2007). Chemical Engineering Science 62:246-255 |
|
|
Tang, Peters, Kuipers, Kreibitzsch, & van der Hoef. AIChE J., 61(2), pp.688-698 (2015). |
|
|
Yin, X, Sundaresan, S. (2009). AIChE Journal 55:1352-1368 This model has a lubrication cutoff distance, LAM_HYS, that can be specified. |
|
|
Gao, X., Li, T., Sarkar, A., Lu, L., Rogers, W.A. Development and Validation of an Enhanced Filtered Drag Model for Simulating Gas-Solid Fluidization of Geldart A Particles in All Flow Regimes. Chemical Engineering Science, 184, 33-51, 2018. |
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|
Sarkar, A., Milioli, F.E., Ozarkar, S., Li, T., Sun, X.,Sundaresan, S., 2016. Filtered sub-grid constitutive models for fluidized gas-particle flows constructed from 3-D simulations. Chem. Eng. Sci., 152, 443-456. |
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|
Radl, S., Sundaresan, S., 2014. A drag model for filtered Euler-Lagrange simulations of clustered gas-particle suspensions. Chem. Eng. Sci., 117, 416-425. |
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|
Tenneti, S., Garg, R., Subramaniam, S., 2011. Drag law for monodisperse gas solid systems using particle-resolved direct numerical simulation of flow past fixed assemblies of spheres. Int. J. Multiph. Flow, 37(9), 1072-1092. |
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G.H. Ganser, A rational approach to drag prediction of spherical and nonspherical particles, Powder Technol. 77 (1993) 143-152. This model requires specification of a sphericity and a reference length (typically the bed diameter) |
|
|
Invoke user-defined drag law. (usr_drag.f) |
|
|
(TFM only). see GIDASPOW |
|
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(TFM only). see GIDASPOW_BLEND |
|
|
(TFM only). see WEN_YU |
|
|
(TFM only). see KOCH_HILL |
8.3.1.25. DRAG_C1¶
Data Type: DOUBLE PRECISION
Quantity for calibrating Syamlal-O’Brien drag correlation using Umf data. This is determined using the Umf spreadsheet.
8.3.1.26. DRAG_D1¶
Data Type: DOUBLE PRECISION
Quantity for calibrating Syamlal-O’Brien drag correlation using Umf data. This is determined using the Umf spreadsheet.
8.3.1.27. LAM_HYS¶
Data Type: DOUBLE PRECISION
The lubrication cutoff distance for HYS drag model. In practice this number should be on the order of the mean free path of the gas for smooth particles, or the RMS roughness of a particle if they are rough (if particle roughness is larger than the mean free path).
8.3.1.28. SPHERICITY_DG¶
Data Type: DOUBLE PRECISION
Particle sphericity (between zero and one) used in the DIFELICE_GANSER drag law.
8.3.1.29. REF_LENGTH_DG¶
Data Type: DOUBLE PRECISION
Reference length (typically the bed diameter) used in the DIFELICE_GANSER drag law.
8.3.1.30. SUBGRID_TYPE¶
Data Type: CHARACTER
Applies to Solids Model(s): TFM
Subgrid models.
Name |
Default? |
Description |
|---|---|---|
|
Igci, Y., Pannala, S., Benyahia, S., and Sundaresan S. (2012). Industrial & Engineering Chemistry Research, 2012, 51(4):2094-2103 |
|
|
Milioli, C.C., Milioli, F. E., Holloway, W., Agrawal, K. and Sundaresan, S. (2013). AIChE Journal, 59:3265-3275. |
8.3.1.31. FILTER_SIZE_RATIO¶
Data Type: DOUBLE PRECISION
Applies to Solids Model(s): TFM
Ratio of filter size to computational cell size.
8.3.1.32. SUBGRID_WALL¶
Data Type: LOGICAL
Applies to Solids Model(s): TFM
Flag for subgrid wall correction.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Do not include wall correction. |
|
Include subgrid wall correction. |
8.3.1.33. MODEL_B¶
Data Type: LOGICAL
Shared gas-pressure formulation. See Syamlal, M. and Pannala, S. “Multiphase continuum formulation for gas-solids reacting flows,” chapter in Computational Gas-Solids Flows and Reacting Systems: Theory, Methods and Practice, S. Pannala, M. Syamlal and T.J. O’Brien (editors), IGI Global, Hershey, PA, 2011.
Name |
Default? |
Description |
|---|---|---|
|
◉ |
Use Model A. See J.X. Bouillard and R.W. Lyczkowski (1991), Powder Tech, 68:31-51. |
|
Use Model B. See Bouillard, J.X., Lyczkowski, R.W., Folga, S., Gidaspow, D., Berry, G.F. (1989). Canadian Journal of Chemical Engineering 67:218-229. |
8.3.1.34. NSCALAR¶
Data Type: INTEGER
- The number of user-defined scalar transport equations
to solve.
8.3.1.35. PHASE4SCALAR(SCALAR EQUATION)¶
Data Type: INTEGER
\(1 \le Scalar Equation \le 100\)
The phase convecting the indexed scalar transport equation.