Thermal meshing

A thermal model consists of elements to model conduction, radiation, and simple convection.

This section describes how to build a mesh for these thermal objects.

Conduction occurs whenever thermal elements share nodes.

Conduction can be modeled using 3D, 2D, 1D, and 0D element types. You can model complex geometry combined with many different element types and material types, both isotropic and orthotropic.

Since the thermal solver uses a control volume approach, there is no need to refine the mesh at the interface between different materials. However, some care must be taken when meshing between different element types, as detailed in Special considerations for thermal meshing.

Conduction modeling

Because the thermal solver uses a control volume formulation for the solution, the element's nodes are used only to define the element's geometry. The nodes do not become calculation points in the numerical thermal model as they do with the finite element method.

A calculation point is established at each element's center of gravity. In addition:

• For a 3D element, an additional calculation point is added at the midpoint of each 2D face of the element

• For a 2D element, an additional calculation point is added at the midpoint of each 1D edge of the element.

	Element
	Element center of gravity and calculation point
	Conductances
	Node
	Additional boundary calculation points

A conductance is established using an algorithm which constrains a piecewise-linear element temperature function to satisfy the governing Partial Differential Equation (PDE) for conduction.

The centroidal node is used to compute distributed heat transfer (radiation, convection, and heat flux). Its temperature is computed assuming a piecewise-linear temperature distribution in the element.

A boundary condition in the thermal solver is applied at the calculation point at the element's center of gravity (CG).

For example, if you specify a fixed temperature for an element, you are actually fixing the temperature at the CG of the element, and not the temperature of the entire element.

The heat flow into the centroidal node is distributed to the boundary calculation points. The thermal solver interpolates the temperature results from the calculation points to the element nodes for post processing and the CG temperature is kept as the element temperature.

How do I

Create a primitive

Learn more

Fluid meshing

Immersed boundary meshing

Duct network meshing

Primitives for Simcenter 3D Space Systems Thermal

Axisymmetric thermal modeling in non-axisymmetric solutions

Look up more details

Meshing for Simcenter 3D Thermal/Flow, Electronic Systems Cooling, Space Systems Thermal

Special considerations for thermal meshing

Working with multi-layer shell elements

Geometry creation for body-fitted fluid meshing

Geometry preparation for immersed boundary method

Defining the mesh size for fluid modeling

Node to geometry matching in large dimension models

Meshing for turbulence modeling

Meshing consideration and wall functions

Thermal and flow element quality

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Simcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal boundary conditions

Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal

Thermal meshing, Simcenter 3D 2021.1 Series

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