How to define porosity in Ansys Fluent ?

 ANSYS Fluent is a software for computational fluid dynamics (CFD) that can simulate various phenomena involving fluid flow, heat transfer, and chemical reactions. One of the features of ANSYS Fluent is the ability to model porous media, such as packed beds, filter papers, perforated plates, etc

To define porosity in ANSYS Fluent, you need to specify a cell zone in which the porous media model is applied and the pressure loss in the flow is determined by your inputs. There are two approaches to set up the porous media model:

In addition to the source term in the momentum equation, you also need to define the porosity value for the porous cell zone. The porosity is a dimensionless quantity that indicates the fraction of the cell volume that is occupied by fluid. The porosity affects the calculation of material properties, heat transfer, reaction source terms, and body forces in the porous medium. You can enter a constant value for the porosity or use a user-defined function (UDF) to specify a spatially varying porosity

To define porosity and resistance coefficients in ANSYS Fluent using the graphical user interface (GUI), you can follow these steps:

• Go to Cell Zone Conditions panel and select the cell zone that you want to model as porous.
• Enable Porous Zone option and click Edit.
• In the Porous Zone panel, enter the value for porosity or select UDF option if you have a UDF for porosity.
• Select either Standard or Power-Law option for Resistance Formulation.
• Enter the values for resistance coefficients or select UDF option if you have a UDF for resistance coefficients.
• Click OK to close the Porous Zone panel and Apply to close the Cell Zone Conditions panel.

To define porosity and resistance coefficients in ANSYS Fluent using the text user interface (TUI), you can follow these steps:

• Enable the use of parameters in TUI by using the command: /define/parameters/enable-in-TUI? yes
• In the TUI, type /define/boundary-conditions/set/fluid
• Select the appropriate cell zone by typing its name and hitting Enter.
• Type y to enable Porous Zone option.
• Enter the value for porosity or type udf if you have a UDF for porosity.
• Type standard or power-law for Resistance Formulation.
• Enter the values for resistance coefficients or type udf if you have a UDF for resistance coefficients.
• Type end to exit from fluid boundary conditions.

For more information and examples on how to define porosity in ANSYS Fluent, you can refer to these sources:

• ANSYS FLUENT 12.0 User’s Guide - 7.2.3 Porous Media Conditions 
• Porous medium simulation. Fluid porosity. - Ansys Learning Forum 
• How to define a parameter for Porosity through ANSYS Fluent TUI … 
• Question about Solidification/melting model in Fluent ⁵

You can also watch these videos that demonstrate how to simulate flow through porous media using ANSYS Fluent:

• #Ansys Fluent | Flow Through Porous Media | Part 1/2 
• Ansys Fluent 2020 R1 - Porous Medium Tutorial 
• ANSYS Fluent Tutorial | Application of Periodic Boundary Conditions in Fluid Flow & Heat Transfer |