Set up a hybrid 2D and 3D thermal model

Practice setting up and solving a hybrid thermal model that consists of the 2D axisymmetric part and 3D repetition part of the cyclic symmetric geometry.

Download and extract the part files.

Open the Simulation file

Open the Simulation file and reset the dialog box settings.

  1. Choose File→Open and open compressor\compressorAxisymmetric_sim1.sim.
  2. Choose File→Preferences→User Interface and on the Dialog and Precision page, reset the dialog box memory.
  3. Click OK.
    The model consists of 2D parts for most of the compressor and 3D parts for rotor stages 3 and 4. The model is meshed and all the material and properties are defined. All the boundary conditions are defined in the model except for the rotor stage 4. The solution is created from the condition sequence and contains eight steps.

Connect the 2D and 3D parts of the rotor stage 4

Model conduction between the disk and blade of rotor stage 4 using thermal coupling.

  1. In the Simulation Navigator, under the Solution 1, expand Simulation Objects, right-click the 2D-3D node and choose New Simulation Object → Thermal Coupling.
  2. In the Name group, type Stage_4_2D_to_3D.
  3. For the primary region, select 6 polygon faces. Three on one side, and three on the opposite side. These faces contact with the 2D part.
  4. For the secondary region, select 4 edges of the 2D part. Two edges on one side, and two on the opposite side. Tip: Use filter Polygon Edge.
  5. In the Magnitude group, from the Type list, select Heat Transfer Coefficient.
  6. In the Coefficient box, specify 1000 W/(m2·°C).
  7. In the Additional Parameters group, make sure that the Only Connect Overlapping Elements check box is selected.
  8. Click OK.

Define two-sided stream on face and edge

Define a stream at the tip of the 3D blade with two-sided stream on edges and faces.

  1. In the Simulation Navigator, right-click Load Container and choose New Folder.
  2. Type Stream on Face-Edge.
  3. Right-click the Stream on Face-Edge node and choose New Load → Thermal Stream .
  4. From the type list, select Two-Sided Stream on Edges and Faces.
  5. In the Name box, type Stream 36.
  6. In the Boundary Condition ID box, type 36.
  7. In the Path Selection - Side A group, click Select Object.
  8. In the graphics window, select the edge of the 2D part.
    Make sure the stream direction is from left to right. If not, click Reverse Direction .

  9. In the Region - Side B group, click Select Object.
  10. In the graphics window, select the polygon face.
    Tip: Use filter Polygon Face.

  11. In the Direction - Side B group, click Specify Vector, and select XC-axis.
  12. In the Auto-Connect Options group, select Automatically Determine Mass Flow and Automatically Determine Inlet Temperature check boxes.
    The software automatically determines mass flow, inlet temperature, and reverse mass flow knowing the upstream and downstream for the current stream.
  13. From the Fluid Materials list, select Air.
  14. In the Stream Conditions group, in the Absolute Pressure box, type P30 MPa.
  15. In the Heat Transfer Coefficient box, type 100 W/(m2·°C).
  16. Click OK.
  17. In the Simulation Navigator, next to Simulation Objects and Loads, click to hide the nodes.

Define Cyclic Symmetry for the blade

Define the Cyclic Symmetry boundary condition to scale the material and convective areas to consider the number of blades.

  1. Right-click the 2D-3D node and choose New Simulation Object → Cyclic Symmetry .
  2. Make sure you choose Manual Cyclic Symmetry.
  3. In the Name group, type Cyclic Symmetry - stage 4.
  4. In the Source Region group, click Create Region, rotate the model if needed, and select the displayed polygon face.
  5. Click OK.
  6. In the Target Region group, click Create Region.
  7. Rotate the model and select the opposite polygon face.
  8. Click OK.
  9. In the Direction group, from the Local list, select X-axis, Y-axis, Origin.
  10. Click CSYS Dialog .
  11. In the Origin Point group, click Point Dialog and click OK.
    The origin of the Absolute - Work Part has been selected.
  12. In the X-axis group, select YC-axis.
  13. In the Y-axis group, select ZC-axis.
  14. Click OK.
  15. In the Segments group, click Calculate Segment.
    The Calculated Number of Segments box displays 81.0005462498997.
  16. Select the Override Calculated Number of Segments (NSEG) check box and type 81 in the Number of Segments (NSEG) box.
  17. Click OK.

Connect the created stream with existing streams

Create junction connections between streams.

  1. Right-click the Junctions node and choose New Simulation Object → Junction.
  2. In the Incoming Streams group, select Stream 35 from the Stream 1 list and Stream 34 from the Stream 2 list.
  3. In the Outgoing Streams group, select Stream 36 from the Stream 1 list.
  4. Click OK.

Solve the model

Solve the model and monitor its completion.

  1. Right-click the Solution 1 node and choose Solve.
  2. Click OK.
    When the solution is complete, the Analysis Job Monitor displays the status as Completed Successfully.
  3. Close the Information window.
  4. Click Cancel on the Analysis Job Monitor dialog box.

Display temperature results

Display temperature results.

  1. In the Post Processing Navigator, double-click the Thermal node to load the results.
  2. Expand Thermal→ Time 2000.0 → Increment 1, 2.000E+03s → Temperature - Nodal.
  3. Expand the Post View 1 → Mesh Collector node, and clear the OD Elements check box.
  4. Choose Results tab→Animation group→Animate .
  5. From the Animate list, select Iterations.
  6. Click Play , then Stop .
  7. Click Close.

Display axisymmetric results

Display results for axisymmetric elements as a 3D model using Axisymmetric Options.

  1. In the Post Processing Navigator, right-click the Post View and choose Edit Result.
  2. In the Coordinate System group, select Absolute Cylindrical from the list.
  3. In the Symmetric Result Options group, click Set Symmetric Results.
  4. From the Display list, select 3D Model.
  5. Click OK.
  6. Choose Results tab → Display group → Feature .
  7. Choose Results tab → Display group → Cutting Plane Options .
  8. In the Cut Direction group, from the Axis list, select YC .
  9. In the Cut Position group, select the Apply Immediately check box.
You have completed this lab.