OS-T: 1385 Heat Transfer Analysis on Piston Rings with GAP Elements

Create PGAP and PGAPHT property before creating gap elements.

1. In the Model Browser, right-click and select Create > Property.
   A default PSHELL property template displays in the Entity Editor below the Model Browser.
2. In the Entity Editor, set the Name to PGAP.
3. For Card Image, select PGAP from the drop-down menu and click Yes to confirm.
4. Set U0= to 0.0.
5. Check the box next to MU1_opts.
6. Click on the field next to Options and select FREEZE from the drop-down menu.
7. Check the box next to PGAPHT.
8. Check the box next to KAHT_opts.
   KAHT=AUTO determines the value of KAHT for each gap element using the conduction of surrounding elements.

   The PGAP and PGAPHT definition should be the same.

   The heat transfer conduction property of gap elements has been created.

   
   
   Figure 2.

1. In the Model Browser, right-click and select Create > Component.
   A default component template is now displayed in the Entity Editor below the Model Browser.
2. For Name, enter PGAP.
3. For Property, click Unspecified > Property.
4. In the Select Property dialog, select PGAP and click OK.
   PGAP should be set to current component automatically.

   
   
   Figure 3.

5. Select the 1D page. Click gaps and go to the create subpanel.
6. Check the option nodes-elems.
7. Click the highlighted nodes button and click by sets.
8. Check the box in front of GAPgrids and click select.
9. Click the highlighted elems button and click by sets.
10. Check the box in front of GAPelems and click select.
11. Face nodes need to be picked for the solid elements in GAPelems.
12. Go to the Model Browser and hide Ring2 under Component.
    The component Ring1 should be displayed on the screen and the inner layer solid elements should be highlighted.
13. Click face nodes and select the nodes on the inner surface of the highlighted solid elements, as shown below.

    
    
    Figure 4. Face Nodes

14. Click property= and select PGAP.
    If the CGAPG elements are created in predefined GAP component, there is no need to specify the property here since GAP is already linked to PGAP property.
15. Click create.
    The CGAPG elements with heat transfer conduction property are created.

    
    
    Figure 5. Overview of CGAPG Elements

    As described at the beginning of the tutorial, the heat transfer boundary condition SPC_heat and heat flux input flux are predefined in the model. An OptiStruct steady state heat conduction loadstep, referring to SPC_heat and flux, has been defined as well. The heat transfer results are requested in Loadsteps panel. Refer to tutorial OS-T: 1080 Coupled Linear Heat Transfer/Structure Analysis for the details on how to define heat transfer boundary condition, heat flux, and the output request.

    Without PGAPHT, the heat cannot be transferred through the gap elements. In this case, the outer ring remains zero degree and the inner ring takes all heat, as shown in the temperature results in Figure 6. Run the completed model and compare the results with PGAPHT to the results below.

    
    
    Figure 6. Temperature Results without PGAPHT