8.1.3 Using a User-Defined Materials Database

In addition to the Fluent Database Materials dialog box, you can also use or create a user-defined materials database using the User-Defined Database Materials dialog box. You can browse and do the following:

• select from existing user-defined databases

• copy materials from a user-defined database

• create a new database, create new materials

• add them to the user-defined database

• delete materials from the database

• copy materials from a case to a user-defined database

• view the database

The following sections will address each of these functionalities in detail.

Opening a User-Defined Database

If you have a database of custom materials as .scm files with data saved in the specified format you can open these databases in ANSYS FLUENT and use them to define the materials in your problem setup.

Examples:

The prescribed format for saving material properties information is shown here for air and aluminum. These files can be created in a text editor and saved with a .scm extension.

 ((air
  fluid
  (chemical-formula . #f)
  (density (constant . 1.225)
  (premixed-combustion 1.225 300))
  (specific-heat (constant . 1006.43))
  (thermal-conductivity (constant . 0.0242))
  (viscosity (constant . 1.7894e-05)
  (sutherland 1.7894e-05 273.11 110.56)
  (power-law 1.7894e-05 273.11 0.666))
  (molecular-weight (constant . 28.966))
  )

 (aluminum
  solid
  (chemical-formula . al)
  (density (constant . 2719))
  (specific-heat (constant . 871))
  (thermal-conductivity (constant . 202.4))
  (formation-entropy (constant . 164448.08))
  ))

To select a user-defined database, click the User-Defined Database... button in the Create/Edit Materials dialog box. This will open the Open Database dialog box.

Figure 8.1.3: Open Database Dialog Box

Click the Browse... button, select the database in the Select File dialog box (see Section  2.1.6) that opens and click OK. Click OK in the Open Database dialog box to open the User-Defined Database Materials dialog box.

Viewing Materials in a User-Defined Database

When an existing user-defined database is opened, the materials present in the database are listed in the User-Defined Database Materials dialog box. You can select the material type in the Material Type drop-down list and the corresponding materials will appear in the User-Defined Fluid Materials, User-Defined Solid Materials or other similarly named list (the list's name will be the same as the material type you selected).

Figure 8.1.4: User-Defined Database Materials Dialog Box

The properties of the selected material will appear in the Properties section of the dialog box. This dialog box is similar to the Fluent Database Materials dialog box in function and operation.

Copying Materials from a User-Defined Database

The procedure for copying a material from a custom database is as follows:

1.   In the Create/Edit Materials dialog box, click the User-Defined Database... button and open the database from which you want to copy the material.

2.   In the User-Defined Database Materials dialog box of the selected database, select the type of material ( fluid, solid, etc.) in the Material Type drop-down list.

3.   In the User-Defined Fluid Materials list, User-Defined Solid Materials list, or other similarly named list (the list's name will be the same as the material type you selected in the previous step), choose the materials you wish to copy by clicking on them. The properties are displayed in the Properties area.

4.   If you want to check the material properties, use the scroll bar to the right of the Properties area to scroll through the listed items.

5.   Click on the Copy button. The selected materials and their properties will be copied from the database into your local list, and your copy of the properties will now be displayed in the Materials task page.

  To copy all the materials from the database in one step, click the shaded icon to the right of the User-Defined Materials title and click Copy.

If a material with the same name is already defined in the case, ANSYS FLUENT will prompt you to enter a new name and formula in the New Material Name dialog box (see Section  5) . Enter a new name and formula in the respective fields and click OK to make a local copy of the material.

Figure 8.1.5: New Material Name Dialog Box

6.   Close the User-Defined Database Materials dialog box.

After copying a material from the database, you may modify its properties or change its name, as described earlier in Section  8.1.2. The material in the database will not be affected by any changes you make to your local copy of the material.

Copying Materials from the Case to a User-Defined Database

You can copy materials that are defined in your problem setup to an existing or new material database. The procedure for copying materials from the case file to a database is as follows:

1.   In the Create/Edit Materials dialog box, click User-Defined Database....

2.   In the Open Database dialog box, select the database to which you want to copy the material. If you want to create a new database, enter the name of the new database in the Database Name field and click OK. A Question dialog box (see Section  2.1.6) will ask you to confirm if you want to create a new file. Click Yes to confirm.

3.   In the User-Defined Database Materials dialog box, click Copy Materials From Case..... This will open the Copy Case Material dialog box.

Figure 8.1.6: Copy Case Material Dialog Box

(a)   In the Copy Case Material dialog box, select the materials that you want to copy.

  To select all the materials, click on the shaded icon to the right of the Case Materials title. Clicking on the unshaded icon will deselect the selections in the list.

(b)   Click Copy and close the dialog box.

Note:   Do not copy materials one by one. This will result in previously copied materials getting overwritten by the new ones. Instead, select all the materials to be copied at once and click Copy.

Modifying Properties of an Existing Material

You can modify the properties of an existing material and use the modified material in the problem setup and save the modified material to the materials database.

1.   In the Materials task page, click on the User-Defined Database... button and open the database that you want to use.

(a)   In the User-Defined Database Materials dialog box of the selected database, select the type of material ( fluid, solid, etc.) in the Material Type drop-down list.

(b)   In the User-Defined Fluid Materials list, User-Defined Solid Materials list, or other similarly named list. The name of the list will be the same as the material type you selected in the previous step. Select the material to be modified.

(c)   Click Edit... to open the Material Properties dialog box.

i.   In the Materials Properties list, select the property to be modified and click Edit... to open the Edit Property Methods dialog box.

ii.   Select the method to be modified in the Material Properties list of the Edit Property Methods dialog box and click Edit... under Edit Properties, in order to modify the properties.

iii.   Make the changes in the corresponding method dialog box and click OK.

iv.   Click Apply in the Material Properties dialog box.

(d)   To use the modified material in the problem setup, click Copy in the User-Defined Database Materials dialog box and close the dialog box.

(e)   To save the modified material to the database, click Save.

Creating a New Materials Database and Materials

Using the User-Defined Database Materials dialog box, you can create a new materials database, copy materials to this database, and also create new materials from scratch. The procedure for creating a new database and add new materials to the database is as follows:

1.   In the Materials task page, click User-Defined Database....

2.   In the Open Database dialog box, enter the name of the database that you are creating and click OK.

3.   A dialog box will appear asking you confirm the creation of a new file. Click Yes to confirm.

  This will open a blank User-Defined Database Materials dialog box (Figure  8.1.7) .

Figure 8.1.7: User-Defined Database Materials Dialog Box: Blank

4.   Click New... in the User-Defined Database Materials dialog box. This will open a blank Material Properties dialog box.

Figure 8.1.8: Material Properties Dialog Box: Blank

(a)   In the Material Properties dialog box , under Types, select the material type. You can select from fluid, solid, inert-particle, droplet-particle, combusting-particle, and mixture materials.

(b)   Enter the name and formula (if required) of the material that you are creating in the Name and Formula fields.

(c)   Depending on the type of material selected in the Types list, properties applicable to that material type will appear in the Available Properties list. Select the properties that are applicable for the material that you are defining by clicking on them.

(d)   Click the $\gg$ button to move these properties to the Material Properties list on the right and click Apply. You can use the $\ll$ button to move the property from the Material Properties list to the Available Properties list.

5.   To edit the parameters that define a property, select the property in the Material Properties list and click Edit.... This opens the Edit Property Methods dialog box.

Figure 8.1.9: Edit Property Methods Dialog Box

(a)   The methods that can be used to define the selected property are listed in the Available Properties list. You can select one or more methods and specify them for the material that you are defining, by selecting and moving them to the Material Properties list.

(b)   To modify each of these methods, you can select the method in the Edit Properties drop-down list and click Edit.... This will open the corresponding property dialog box, where you can modify the parameters used by the property method. Refer to Sections  8.2 to 8.16 for details of these properties, methods used to define the properties and the parameters for each method.

(c)   Click OK in the Edit Property Methods dialog box.

6.   Click Apply in the Material Properties dialog box.

7.   Click Save in the User-Defined Database Materials dialog box to save the changes to the new materials database.

Similarly, you can also append new materials to an existing database. Select the existing database in the Open Database dialog box. Create new materials and click save to append these materials to the existing database.

Deleting Materials from a Database

To delete a material from a database, click the User-Defined Database button in the Create/Edit Materials dialog box. Select the database and click OK in the Open Database dialog box. Select the Material Type and the materials that you want to delete in the User-Defined Materials list and click Delete. Click Save to save the database.