Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal > Workflow for thermal and flow analyses > 1D duct flow networks
Create a duct flow network and model heat transfer using 3D solid elements
This example shows how to create a duct network with 1D duct elements and model duct convection with surrounding 3D solid elements.
You will create surfaces and curves that run along the centerlines of the ducts. These curves are meshed and used to model fluid flow.
Make sure that there are no duplicate nodes at the point where two curves join. You can use mesh mating conditions between the adjoining parts.
Display the FEM file.
Choose Home tab→Properties group→Mesh Collector , and for each segment of the network, with a consistent duct cross section, create one mesh collector.
From the Type list, select Duct.
In the Properties group, from the Material list, select a fluid material.
From the Section list, select a solid cross section area.
Click OK.
Choose Home tab→Mesh group→1D mesh to create a 1D mesh on the duct curves.
In the Objects to Mesh group, select the Auto Chain Selection check box to ensure that all the duct elements point in the same direction.
In the Objects to Mesh group, select the Merge Node check box to ensure that there are no duplicate nodes.
Assign the meshes to the mesh collectors according to their cross sections.
Click OK.
Choose Home tab→Mesh group→3D mesh to create a 3D mesh on the duct surfaces.Ensure you define the 3D mesh collector using a thermal material, thickness, and thermo-optical properties if required.
In the Simulation Navigator, right-click the FEM node, and choose Display Simulation→Simulation file.
Choose Home tab→Loads and Conditions group→Duct Flow Boundary Conditions to create as many boundary conditions as required by your model.
Choose Home tab→Loads and Conditions group→Immersed Ducts to model duct convection with surrounding 3D solid elements.
In the Simulation Navigator, right-click the Solution node, and choose Edit.
In the Solution dialog box, on the Ambient Conditions page, set ambient values including the gravity vector.
How do I
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Create a standard cross section
Learn more
1D duct flow networks
Duct analysis workflow
Duct Flow Boundary Conditions
1D meshing
Ensuring consistent 1D element orientation during mesh creation
Look up more details
Modeling ducts with 1D elements
Modeling ducts and their walls with 1D elements
Modeling ducts with 1D elements and their walls with 2D elements
Modeling the interface between ducts and 3D fluid elements
Modeling ducts inside 3D solid elements
Understanding ducts and area definition
Solver calculation for duct elements
Solver calculation for duct with mass flow elements
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Create a duct flow network and model heat transfer using 3D solid elements, Simcenter 3D 2021.1 Series
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Source: https://docs.sw.siemens.com/en-US/doc/289054037/PL20200601120302950.advanced/xid1676509_v1 · retrieved 2026-07-17