Workflow for thermal and flow analyses

The basic workflow for modeling heat transfer and fluid dynamics is the same in any Simcenter 3D Thermal/Flow, Simcenter 3D Electronic Systems Cooling, or Simcenter 3D Space Systems Thermal model. The most important rule to remember with all analysis workflows is to start with as simple a model as possible and add detail as required. Initially, you should do the following:

• Omit less significant parts or features in an assembly.

• Simplify geometric representations.

• Use a coarse element mesh.

• Perform a simple analysis. For example, perform flow analysis only instead of coupled analysis, or steady state analysis instead of transient analysis.

• Check solution results using basic heat transfer calculations and fluid flow principles.

After you are confident that the initial model is reasonable, add details and use a finer mesh if necessary.

Step	Summary	Detailed help topic
1.	Create or import the geometry.	Create the geometry in the Modeling application or open an existing part file.	Part modeling overview
2.	Create the FEM and Simulation files.	When you create new FEM and Simulation files for thermal and flow analyses, select the appropriate solver, analysis, and solution types depending on your licenses.	Create new FEM and Simulation files
3.	Simplify the geometry.	Simplify the geometry in the idealized part and create fluid volumes where they are needed.	Model preparation
4.	Mesh your geometry.	Mesh solids and fluid volumes taking into consideration the type of analysis that you want to do and the available resources. You create meshes of 3D, 2D, 1D, or 0D elements that are stored in specified mesh collectors.	Meshing for Simcenter 3D Thermal/Flow, Electronic Systems Cooling, Space Systems Thermal
5.	Specify physical and material properties to all mesh collectors.	For each mesh collector, choose the material, physical, and thermo-optical properties that are best suited to your analysis. Depending on what you are modeling, different physical and material properties are necessary.Conduction modelingConduction is always modeled between elements that share nodes, providing the following conditions are met:Thermal conductivity (material property) for the elements must be defined.2D elements must have thickness physical property defined and 1D elements must have a beam section defined.Fluid flow modeling3D elements (body-fitted mesh) or 3D cells (immersed boundary mesh) that are assigned a fluid material participate in the flow solution.Convection modelingConvection is automatically simulated where fluid elements touch solid walls, or where Flow Surface boundary conditions are explicitly created. Convection properties can be tailored where appropriate.Radiation modelingOnly surfaces can radiate heat: faces of 3D solid elements, 2D shell elements, 1D beam elements with assigned sections, and 0D concentrated mass elements with specified diameter. The Radiation check box in the Thermo-Optical Properties group in the Mesh Collector Attributes dialog box must be selected for elements to participate in radiation exchange.	Defining materials for Simcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems ThermalDefining physical properties
6.	Apply boundary conditions and create modeling objects.	In the Simulation file, a solution is created to hold the loads, constraints, and simulation objects that you can define. For example, you can define flow boundary conditions, additional heat paths, thermal heat loads, fixed temperatures, radiative sources, orbital data. Although boundary conditions can be assigned to geometric features of the model, for example points, edges, faces, or solid bodies, ultimately the boundary conditions are always applied to elements by the thermal and flow solvers.Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal modeling objects modify selected simulation objects or are directly applied to the complete model.	Simcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal boundary conditionsSimcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal simulation objects
7.	Modify solution attributes and solver parameters.	In the Solution dialog box, you define your analysis as steady state or transient and modify other solution options such as:Initial conditions for the complete modelAmbient conditionsResult requestsTransient options3D flow optionsAdjust solver parameters in the Solver Parameters dialog box to improve convergence, to speed calculation time, or to adjust for unusual modeling situations.	Solution optionsAdjusting solver parameters
8.	Solve the thermal and/or flow solution.	During the analysis, the Solution Monitor displays error, warning, and information messages for the module which is currently executing. You can also track:The convergence of the thermal and flow solvers.The temperature, fluid velocity, and fluid pressure from the complete model.After every solution, take the time to verify the convergence of the model. Review the message files for global heat balance and mass balance for flow problems. Investigate warnings and check the view factor sums for radiation problems.	Solving the model
9.	Post process your results.	Display your results in the Post Processing Navigator and prepare a report.After you run an analysis, you can refresh results and reports using changed results and report requests.	Using the Post Processing NavigatorRefresh results and reports in a solution

Learn more

Modeling additional heat paths

Modeling convection

Identifying flow enclosures

Axisymmetric thermal modeling in non-axisymmetric solutions

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Workflow for thermal and flow analyses, Simcenter 3D 2021.1 Series

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