Fire Dynamics Simulator

Transcription

1 Fire Dynamics Simulator Using FDS Find out more information about FDS at the primary FDS website FDS runs on Windows, Mac, and Linux. You can download FDS from the above website, or you can check out the FDS SVN repository and compile it yourself by using gfortran or the Intel fortran compilers. Solid Works to FDS This tutorial is for those that have access to CAD programs such as Solid Works to setup up geometry for later export to FDS. Note that this tutorial will work for other CAD programs as long as the the exported file is a VRML (.wrl) file. Exporting the VRML file from Solid Works When the desired geometry has been finished in Solid Works, the file will have to be saved as a VRML (.wrl) file. Click File->Save As.

2 In the "Save as type" drop down menu choose the VRML (.wrl) option.

3 Click on the "Options" button underneath the "Save as type" drop down menu. Under the "Output as" section of the options window, click on the "Version" drop down menu.

4 Choose the "VRML '97" option.

5 Click "OK" Click "Save" and you should now have a VRML (.wrl) file containing your Solid Works geometry. Necessary Programs and Plugins for Conversion Download Blender here. Download BlenderFDS plugin here. Installing the BlenderFDS plugin In order to define surface and object properties for the geometry to be exported to FDS, the BlenderFDS plugin needs to be installed.

6 Click on File->User Preferences

7 Click on the "Addons" tab at the top and then click on the "Install from File..." button on the bottom of the window (highlighted green) Choose the directory to which you downloaded the BlenderFDS plugin. From here choose the BlenderFDS.zip (after the initial unpacking there should be another.zip file containing the Python code of the plugin) and then click on the "Install from File..." button.

8 To activate the plugin simply search for the plugin using the search bar (highlighted green) and check the box at the right (highlighted green) Importing the VRML file into Blender

9 Before importing the VRML file the, editing environment will have to be setup. First delete the box in the scene by clicking near it and pressing "x" on your keyboard. This will bring up a drop down menu confirming the deletion. Move the mouse over to the top right (highlighted green). The camera and light can be deleted from here (these will not be needed for exporting to FDS).

10 Delete the camera by right clicking the camera and selecting "Delete" Delete the light by right clicking the light and selecting "Delete"

11 Click File->Import->X3D Extensible 3D(.x3d/.wrl)

12 Navigate to the directory where the.wrl file is located. Highlight the file by clicking it and then click the "Import X3D/VRML2" button to import the file. The geometry should now be imported. Some editing will need to be done to ensure that the geometry lines up with the coordinate axis in FDS. Editing the imported VRML file

13 Clicking on the object will produce a drop down menu on the left. First the "Rotate" button (highlighted green) is double clicked (a single click results in rotation due to mouse movement). After double clicking an "Angle" and "Constraint Axis" menu appears near the bottom of the menu (highlighted green) The Y and Z axis are constrained and the geometry is allowed to rotate 90 deg about the X axis such that it is now level with the ground.

14 The "Rotate" button is double clicked again and new constraint axis are assigned to align the geometry.

15 Next click the imported object (in this case the "ShapedIndexedFaceSet" object) from the drop down menu on the top right (highlighted green). This will bring up surface and object properties. Click the "Surface" group and then scroll down to the bottom of the menu to find the FDS options.

16 Click the "Solid" group and then scroll down to the bottom of the menu to find the FDS options.

17 Under the "XB:" drop down menu, choose the "Edges" option. Exporting from Blender to FDS Click File->Export->Fire Dynamics Simulator Case (.fds)

18 Choose the directory in which you would like to save your geometry

19 Open the geometry with your preferred text editor. The file can then be edited to include mesh properties, thermophysical properties, etc. Note: These changes can be made with the BlenderFDS plugin but is beyond the scope of this tutorial. Geometry in Smokeview