Ansys: Difference between revisions

UDFs can be used to customize Discrete Phase Models (DPM) as described in <I>Part III: Solution Mode | Chapter 24: Modeling Discrete Phase | 24.2 Steps for Using the Discrete Phase Models| 24.2.6 User-Defined Functions</I> of the <I>2024R2 Fluent Users Guide</I> and section <I>Part I: Creating and Using User Defined Functions | Chapter 2: DEFINE Macros | 2.5 Discrete Phase Model (DPM) DEFINE Macros</I> of the <I>2024R2 Fluent Customization Manual</I> available [https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/prod_page.html?pn=Fluent&pid=Fluent&lang=en here]. Before a DMP based UDF can be worked into a simulation, the injection of a set of particles is typically defined by specifying "Point Properties" with variables such as source position, initial trajectory, mass flow rate, time duration, temperature and so forth depending on the injection specifics/options.  This can be done in the gui by clicking the Physics panel, Discrete Phase to open the <I>Discrete Phase Model</I> box and then clicking the <I>Injections</I> button.  Doing so will open an <I>Injections</I> dialog box where one or more injections can be created by clicking the <I>Create</I> button.  The "Set Injection Properties" dialog which appears will contain an "Injection Type" pulldown with first four types available are "single, group, surface, flat-fan-atomizer". If you select any of these then you can then the "Point Properties" tab can be selected to input the corresponding Value fields.  Another way to specify the "Point Properties" would be to read an injection text file.  To do this select "file" from the Injection Type pulldown, specify the Injection Name to be created and then click the <I>File</I> button (located beside the <I>OK</I> button at the bottom of the  "Set Injection Properties" dialog).  Here either an Injection Sample File (with .dpm extension) or a manually created injection text file can be selected.  To Select the File in the Select File dialog box that change the File of type pull down to All Files (*), then highlight the file which could have any arbitrary name but commonly likely does have a .inj extension, click the OK button.  Assuming there are no problems with the file, no Console error or warning message will appear in fluent.  As you will be returned to the "Injections" dialog box, you should see the same Injection name that you specified in the "Set Injection Properties" dialog and be able to List its Particles and Properties in the console.  Next open the Discrete Phase Model Dialog Box and select Interaction with Continuous Phase which will enable updating DPM source terms every flow iteration.  This setting can be saved in your cas file or added via the journal file as shown.  Once the injection is confirmed working in the gui the steps can be automated by adding commands to the journal file after solution initialization, for example: