CAE Software【Femtet】Murata Software Co., Ltd.
Using the heat sink, heat dissipation of the IC by the natural convection is solved by the steady-state analysis.
The temperature distribution and the heat flux vectors are solved.
Unless specified in the list below, the default conditions are applied.
Item |
Setting |
Analysis Space |
3D |
Model Unit |
mm |
Item |
Setting |
Solver |
Fluid analysis [Bernoulli] Thermal analysis [Watt] |
Analysis Type |
Fluid analysis: Steady-state analysis Thermal analysis: Steady-state analysis |
Laminar Flow/Turbulent Flow |
Select Turbulent Flow |
Option |
Select Take Buoyancy into Account (Natural Convection) |
Layer Mesh Setting for Wall Surface (General Settings) |
Parameters for Automatic Creation Expected Temperature Difference: 50[deg] |
Meshing Setup |
General Mesh size: 10 [mm] |
Detailed Setting |
Relaxation Coefficient (Temperature) |
The relaxation coefficient (temperature) is set at the large value as the default setting will take longer time for convergence.
The substrate (VOL1) and the heat sink (HeatSink) are solid bodies.
The model is a box solid body. The material is Air (000_Air).
Set natural inflow/outflow to the outer boundary condition of Inlet/Outlet.
Body Number/Type |
Body Attribute Name |
Material Name |
Mesh Size |
0/Solid |
VOL1 |
006_Glass_epoxy * |
2.0 |
1/Solid |
VOL2 |
001_Alumina * |
2.0 |
2/Solid |
Air |
000_Air(*) |
– |
14/Solid |
HeatSink |
001_Al * |
2.0 |
* Available from the material DB
IC (VOL2) is set as follows on the Heat Source tab.
Body Attribute Name |
Tab |
Setting |
VOL2 |
Heat Source |
1W |
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Setting |
Outer Boundary Condition |
Fluid-Thermal |
Inlet/Outlet |
Natural Inflow/Outflow Inflow temperature: Use ambient temperature (25[deg]) |
The temperature distributions of the substrate, IC, and heat sink are shown below.
The air is hidden.
For the comparison purpose, the results of Example 6: Cooling of IC by Natural Convection], which is without a heat sink, are shown as well.
The maximum temperature without the heat sink is 105[deg] whereas it is 42[deg] with the heat sink.
The results confirms the effect of the heat sink.
By switching the solver type from thermal to fluid analysis, the flow velocity vectors are shown as below.
The cross section at x=0 is displayed.
In the graphics setup, the 3D vector is set OFF.
Ascending flows are generated between the walls of the heat sink.