Boundary Layer Control In Icepak Classic (Fluids) Using ANSYS Mesher

This article describes the Nimbix cloud workflow recommended to import ANSYS mesh into Icepak classic for boundary layer meshes.  

To start the process of importing ANSYS meshes into Icepak, access ANSYS Platform on NIMBIX through the following steps:

1. Select the desired ANSYS Platform release from the Compute dashboard.


NOTE: If the option is not available in the first-page menu, press on “More” at the bottom of the page as shown in the image below:


2. A splash window will open. Select the ANSYS Workbench Platform option as shown below:


3. Cloud set-up screen opens and here you must choose some of your settings by clicking on the Tabs on the top of the window (General, Optional, etc) one tab at a time.


1. Under Machine type when you click on the caret on the right, you can select the type of machine you want to run your job on. The decision on machine type selection is based on size and complexity of your model and cost associated with the machine type (some machines will have higher RAM, others will only run the job on single CPU, others will have better graphics and therefore higher cost, etc).


NOTE: When running interactive based applications, you’ll find that selecting an NC9 or any NC* machine types should offer significant visual performance over not selecting an NC machine type. By selecting an NC machine, this places a GPU on your head-node, and offers better visual performance. Another thing to keep in mind, is that when running interactively you can use a web-browser, or in some cases for large models or you might consider using RealVNC.

2. Select the number of cores:

The machine type you selected in the previous step, will dictate the increment in the number of cores that you can choose/select. For a very simple and small model, you can leave default selection, which in this case would be “16” or move the scroll bar to the desired number of cores or simply type over “16” the number of cores you wish to run your job on (we left it default in this case):


NOTE: Do not confuse the number of cores with the number of nodes (nodes represent the number of increment of cores that you selected. In the example above, 1 node represents 16 cores, 2 nodes correspond to 32 cores). For pre-processing, meshing, and post-processing operations, select one node with the lowest number of cores to reduce cost (not computationally intensive operations).


1. Assign a JOB LABEL (give a name that will help you keep track of your running jobs. For example, My_Platform_Project):


Leave blank the wall time limit and the IP address. Fill in the information about the Elastic License Server (if required). The Window size needs to be kept as default.


1. Select vault type: Default vault is “Elastic_File”


The “Elastic_File” vault is recommended for small to medium size jobs, such as Icepak projects, simple linear Mechanical Analysis projects, some HFSS and simple Fluent projects (not multi-phase). For any complex and computationally heavy jobs, and where partitioning the job over number of cores becomes challenging, the Performance_SSD vault is strongly recommended. The Performance_SSD vault can be found in the drop-down under “Select Vault” tab (NOTE: requires subscription and extra monthly payment to have access to Performance_SSD vault).

Before submitting your job for running, you can preview your settings under the PREVIEW SUBMISSION tab.

2. You can start your job by clicking on the SUBMIT tab.


After ANSYS Workbench Platform has been successfully launched, you should be able to see the ANSYS Workbench in the preview and can access the window by clicking on it (you can see details on the number of nodes, some information regarding memory, etc):


After clicking “OK” on ANSYS feedback survey participation window, you are inside the Ansys Workbench environment:


ANSYS Workbench is a software environment for performing structural, thermal, and electromagnetic analyses. You can also perform tasks such as geometry creation and optimization, attaching an imported CAD geometry, setting up the finite element model, solving, and reviewing results. 

For this article, we will refer to the CFD analysis of a cold plate that has water (or water mixture) circulating through a tube that is fully embedded in a solid plate (Aluminum, copper, etc).

Here are the steps to follow in order to perform an external mesh import in Ansys Icepak (classic).

1. Grab and drop a Geometry module from the Workbench tree, as shown below:


Note: The geometry could be the full CAD geometry (solid plate and fluid inside the embedded tube) or it can be that of the fluid inside the tube ONLY (if a fluid extraction has been performed in your CAD software or within Design Modeler inside Ansys Workbench). This Geometry module will be used for performing a fine mesh at the boundary between the fluid and the solid tube, in order to capture the boundary layer at the tube’s wall.

For this help article, the fluid extraction was performed within ANSYS Design Modeler (refer to ANSYS help on performing fluid extraction in Design Modeler).


2. Link the Geometry module with a Mesh Module from the Workbench Component Systems as shown below.


3. Open the Mesh module and perform mesh refinement of the fluid object only (suppress the solid bodies in the Ansys Mesh, unless the geometry consists only of the fluid body).


NOTE: Be sure that you select the Physics preference as “CFD”, because certain mesh settings are available based on the physics selected. If you are satisfied with the mesh quality and the boundary layers the refined mesh created, proceed to the next step. Otherwise, perform mesh setting improvement until the mesh is satisfactory. Ensure all in-scope objects (fluid bodies, openings, etc) are included in the ANSYS meshing operations as desired.

4. Perform Mesh Export by going to File > Export > Mesh > FLUENT Input File as shown below.


5. Click on the Export icon that pops-up and save the mesh in the data file and folder where the NIMBIX project is saved:


NOTE: Use a descriptive filename while saving in order to easily identify the mesh file later in the process. 

Note: For the example presented in this article, the mesh was named “TubeMesh” and was saved in the same folder where the Workbench project is saved.


6. Once the mesh file is saved, please close the Ansys Mesh project and proceed to the next step.

7. Within the same Workbench interface, drag and drop a new Geometry module that contains both the solids and the fluid objects. 


8. Perform Geometry simplification using the Tools > Electronics > Simplify feature available in Ansys Design Modeler (this step is necessary in order to create from the CAD objects, Icepak compatible bodies):


9. Once the CAD simplification operation has performed, the CAD objects become Icepak compatible objects, as shown below:


10. In the Workbench interface tree, from Component Systems, drag and drop an Icepak module and link it to the Geometry module, as shown below:


11. Right-click on the Setup row in the Icepak module and select “Edit” to open Icepak project, as shown below:


12. Perform typical Icepak settings (boundary conditions, inlet, outlet, add sources, etc) as required and perform meshing by clicking on “Generate Mesh” icon from the Icepak toolbar. The “Mesh Control” window to enter your mesh settings.


13. To import the fluid mesh generated using ANSYS mesher, click on “Local” tab within the Mesh Control window: 


14. A pop-up window will open. Click on “Edit mesh reuse” and a window will pop up where you can choose the parts for which you want to Import a mesh (in this example, the part for which we created a mesh using Ansys mesher is the fluid body):


15. Once you selected the object that was meshed in Ansys mesher and selected the fluid mesh file from the folder where you saved it, click the Done button and move forward with meshing the solid parts, using the Ansys Icepak meshing capabilities (generate mesh to ensure a good global and local CFD mesh).

16. You can display the mesh, by selected objects, to see if the mesh created in Ansys mesher has been imported correctly. 


17. Pack the Icepak project (generate a .tzr file) from the Workbench interface and continue with setting the boundary conditions, flowrate, fluid type etc within the Icepak stand-alone interface (it is not recommended to run the Icepak from Workbench interface)

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