Restart under Different Boundary Conditionexamples|products|Murata Software Co., Ltd.

Example18 Restart under Different Boundary Condition

General

  • The transient analysis is restarted after the boundary condition is changed from “temperature” to “heat transfer/ambient radiation”.
     

  • The temperature distribution and the heat flux vectors are solved.
     

  • Unless specified in the list below, the default conditions will be applied.

 

Analysis Space

 

Item

Settings

Analysis Space

3D

Model unit

mm

 

Analysis Conditions

Item

Settings

Solver

Thermal Analysis [Watt]

Analysis Type

Transient analysis

Options

N/A

 

The Transient Analysis tab is set up as follows. The initial temperature is 25[deg] and the time step is 10[sec].

The calculation steps are 18 and 72 before and after restart respectively..

 

Initial Setting:

Tab

Setting Item

Settings

Transient analysis

Table

Number

Calculation steps

Output steps

Time step [s]

1

18

1

10

 

Restart

Deselect “Continue from the last session”

Initial Temperature

25[deg]

 

The settings for the restart

Tab

Setting Item

Settings

Transient analysis

Table

Number

Calculation steps

Output steps

Time step [s]

1

72

1

10

 

Restart

Select “Continue from the last session”

Initial Temperature

N/A

 

* After the first leg, change the analysis conditions and boundary conditions. Then start the next leg by clicking Run Mesher/Solver -> Run Solver.

Model

The initial temperature of the cylindrical body is 25[deg]. The top face is set to 300[deg] with the temperature boundary condition.

The boundary condition is changed to the natural convection and the ambient radiation in the next leg.

Body Attributes and Materials

Body Number/Type

Body Attribute Name

Material Name

0/Solid

A001

007_Fe *

* Available from the Material DB

Boundary Conditions

Change the boundary condition of BC_Change in the interval between the first and second transient analyses as follows.

Boundary Condition Name/Topology

Tab

Boundary Condition Type

Settings

BC_Change/Face (in the first leg)

Thermal

Temperature

300[deg]

BC_Change/Face (in the second leg)

Thermal

Heat Transfer/Ambient Radiation

Select “Natural convection (automatic calculation)”.

Also select “Ambient radiation” and set 1.0.

Room temperature : 25[deg]

Outer Boundary Condition

Thermal

Heat Transfer/Ambient Radiation

Select “Natural convection (automatic calculation)”.

Also select “Ambient radiation” and set 1.0.

Room temperature : 25[deg]

 

Results

Diagram below shows the temperature distribution at 90[s].

 

The temperatures of 5 points in the model will be drawn through the following chart setting. The 5 points for the chart are set at regular intervals form the bottom to the top.

 

 

The temperatures increase for the first 180 seconds. But after the boundary condition on the top face is changed, they decrease.