### Thermal Analysis

```Thermal Elements
Jake Blanchard
Spring 2008
Thermal Elements
These elements calculate temperatures in
solids
 There are 1-D, 2-D, and 3-D elements
 All have just 1 DOF per node
 Properties are thermal conductivity (k) for
steady state analysis and density () and
heat capacity (cp) for transient analyses
 Boundary conditions can be temperatures,
 Volumetric heating is also possible

Thermal Elements in ANSYS
LINK 32 – 2-D conduction bar
LINK 33 – 3-D conduction bar
PLANE 35 – 6 node triangle
PLANE 55 – 4 node quad
PLANE 75 – 4 node axisymmetric-harmonic
element
 PLANE 77 – 8 node quad
 PLANE 78 – 8 node axisymmetric-harmonic
element
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More Thermal Elements
SOLID 70 – 8 node solid
 SOLID 87 – 10 node tetrahedral element
 SOLID 90 – 20 node hexahedral element
 SHELL 57 – 4 node
 SHELL 131 – 4 node layered element
 SHELL 132 – 8 node layered element

Real Constants
Area, heat transfer coeff., and emissivity
 None for planar and solid elements
 Thickness for shell element (not
layered)
 Use “Sections” for layered elements

In-Class Problems
T=0 C
 k1=1 W/m-K
 k2=20 W/m-K
1
2
T=100 C
1 cm
10 cm
In-Class Problems
T=0 C
 k1=1 W/m-K
 k2=20 W/m-K
q=104 W/m2
1
2
1 cm
10
cm
In-Class Problems h=1000 W/m2-K
Tb=50 C
 k1=1 W/m-K
 k2=20 W/m-K
q=104 W/m2
1
2
1 cm
10
cm
In-Class Problems T=50 C
 k1=1 W/m-K
 k2=20 W/m-K

Channels are 3 cm
in diameter
2
2 cm
1
15
cm
1 cm
q=104 W/m2
10
cm
In-Class Problems h=1000 W/m2-K
Tb=50 C
 k1=1 W/m-K
 k2=20 W/m-K

Channels are 3
cm in diameter
2
2 cm
1
15
cm
1 cm
q=104 W/m2
10
cm
```