.. _model_setup: .. include:: /icons.rst =========== Model Setup =========== The Model pane is used to specify global project settings. Depending on what is selected, other panes are enabled or disabled. - **Description** allows for a short model description to be provided. This is written in the .OUT file by the solver. - **Solver** specifies the model solver. - *Single phase* is the MFiX fluid solver. This disables all solids model inputs. - *Two-Fluid Model (MFiX-TFM)* treats both the fluid and solids as interpenetrating continua. - *Discrete Element Model (MFiX-DEM)* treats the fluid as a continuum while modeling individual particles and collisions. - *Particle in Cell Model (MFiX-PIC)* treats the fluid as a continuum while using “parcels” to represent groups of real particles with similar physical characteristics. ------- - **Disable the fluid phase** turns off the fluid solver for MFiX-TFM and MFiX-DEM simulations for pure granular flows. The fluid solver cannot be disabled for single phase flows. - **Enable thermal energy equations** solves thermal transport equations for all phases. - **Turbulence Model** incorporates the selected turbulence model. - *None* - *L-Scale Mixing* - Do not include turbulence. - Requires a turbulent length scale definition for all initial condition regions. - *K-Epsilon* - Do not include turbulence. - Requires turbulent kinetic energy and turbulent dissipation definitions for all initial condition regions and all mass and pressure inflow boundary conditions. - **Max turbulent viscosity** has units of :math:`(Pa \cdot sec)` and is used to bound turbulent viscosity. ------- - **Gravity** has units of :math:`({m}/{sec^2})` and defines gravitational acceleration in the x, y, and z directions. ------- - **Drag model** specifies the fluid-particle drag model. This option is only available with the MFiX-TFM and MFiX-DEM solvers. - *Syamlal-O'Brien* [SB1988]_ - Requires the specification of the C1 tuning parameter, 0.8 by default. - Requires the specification of the D1 tuning parameter, 2.65 by default. - *Beestra-van der Hoef-Kuipers* [BVK2007]_ - *Gidaspow* [DG1990]_ - *Gidaspow Blend* [LB2000]_ - *Holloway-Yin-Sundaresan* [HYS2010]_ - Requires the specification of the lubrication cutoff distance, 1e-6 meters by default. - *Koch-Hill* [HKL2001]_ - *Wen-Yu* [WY1966]_ - *User-Defined Function (UDF)* - A custom drag model must be provided in the usr_drag.f file - A custom solver must be built. .. note:: The *polydisperse* tag following a specified drag model indicates that the polydisperse correction factor is available. For additional details see [HBK2005]_, [BVK2007a]_, and [BVK2007b]_. ------- Other advanced options that can be selected include: - Momentum formulation (Model A, Model B, Jackson, or Ishii) - *Model A* - *Model B* - *Jackson* - *Ishii* - Select sub-grid model - *None* - *Igci* [IPBS2012]_ - *Milioli* [MMHAS2013]_ - Sub-grid filter size - Sub-grid wall correction .. note:: There are some restrictions to when using sub-grid models. They are only available with MFiX-TFM simulations using the Wen-Yu drag law, and without turbulence model. Additional restrictions apply. .. [SB1988] Syamlal, M, and O'Brien, T.J. (1988). Simulation of granular layer inversion in liquid fluidized beds, *International Journal of Multiphase Flow*, Volume 14, Issue 4, Pages 473-481, https://doi.org/10.1016/0301-9322(88)90023-7. .. [HKL2001] Hill, R., Koch, D., and Ladd, A. (2001). Moderate-Reynolds-number flows in ordered and random arrays of spheres. *Journal of Fluid Mechanics*, Volume 448, Pages 243-278. https://doi.org/10.1017/S0022112001005936 .. [DG1990] Ding, J. and Gidaspow, D. (1990). A bubbling fluidization model using kinetic theory of granular flow, *AIChE Journal*, Volume 36, Issue 4, Pages 523-538, https://doi.org/10.1002/aic.690360404 .. [LB2000] Lathouwers, D. and Bellan J. (2000). Modeling of dense gas-solid reactive mixtures applied to biomass pyrolysis in a fluidized bed, Proceedings of the 2000 U.S. DOE Hydrogen Program Review, https://www.nrel.gov/docs/fy01osti/28890.pdf .. [WY1966] Wen C.Y., and Yu Y.H. (1966). Mechanics of fluidization, *The Chemical Engineering Progress Symposium Series*, Volume 62, Pages 100-111. .. [BVK2007] Beetstra, R., van der Hoef, M.A., and Kuipers, J.A.M. (2007). Numerical study of segregation using a new drag force correlation for polydisperse systems derived from lattice-Boltzmann simulations, *Chemical Engineering Science*, Volume 62, Issues 1–2, Pages 246-255. https://doi.org/10.1016/j.ces.2006.08.054. .. [HYS2010] Holloway, W., Yin, X., and Sundaresan, S. (2010). Fluid‐particle drag in inertial polydisperse gas–solid suspensions, *AIChE Journal*, Volume 56, Issue 8, Pages 1995-2004. https://doi.org/10.1002/aic.12127 .. [HBK2005] Hoef, M., Beetstra, R., and Kuipers, J. (2005). Lattice-Boltzmann simulations of low-Reynolds-number flow past mono- and bidisperse arrays of spheres: Results for the permeability and drag force. *Journal of Fluid Mechanics*, Volume 528, Pages 233-254. https://doi.org/10.1017/S0022112004003295 .. [BVK2007a] Beetstra, R. , van der Hoef, M. A. and Kuipers, J. A. (2007), Drag force of intermediate Reynolds number flow past mono‐ and bidisperse arrays of spheres. AIChE J., 53: 489-501. https://doi.org/10.1002/aic.11065 .. [BVK2007b] (2007), Erratum. AIChE J., 53: 3020-3020. https://doi.org/10.1002/aic.11330 .. [IPBS2012] Igci, Y., Pannala, S., Benyahia, S., and Sundaresan, S. (2012). Validation studies on filtered model equations for gas-particle flows in risers, *Industrial & Engineering Chemistry Research*, Volume 54, Issue 4, Pages 2094-2103. https://doi.org/10.1021/ie2007278 .. [MMHAS2013] Milioli, C.C., Milioli, F.E., Holloway, W., Agrawal, K. and Sundaresan, S. (2013), Filtered two‐fluid models of fluidized gas‐particle flows: New constitutive relations. *AIChE J.*, Volume 59, Issue 9, Pages 3265-3275. https://doi.org/10.1002/aic.14130