Yeah, there's a write up in SuiteAnswers for it, Answer ID: 28349 https://netsuite.custhelp.com/app/answers/detail/a_id/28349/kw/default%20department%20on%20transaction

Set a Default Department on Sales Orders via Workflow
Published 03/25/2013 11:26 AM   |    Updated 12/26/2017 02:44 AM	  |    Answer Id: 28349
1. Navigate to Customization > Workflow > Workflows > New.
2. Set the following:

   • Name: For example, “Set Default Department”
   • Record Type: Transaction

   • Sub Types: Sales Order
   • Execute as Admin is checked
   • Release Status: Released
   • Event Based: On Create
   • Trigger Type: All

3. Click Save.
4. Click New State.
5. Enter a Name then click Save.
6. Click State 1 > New Action.
7. Click Set Field Value.
8. Set Trigger On = Entry.
9. In the Parameters section, set Field = Department (Main).  
10. In the Value section, mark Static Value and select the default Department value in the Selection field.
11. Click Save.


 

This is an alternate solution for Enhancement 63724  - Default Department on Sales Transactions