Example9 Body-to-Body Heat Radiation(Transient Analysis)

General

  • The temperatures of the two bodies are equalized by 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

m

 

Analysis Conditions

Item

Settings

Solvers

Thermal Analysis [Watt]

Analysis Type

Transient analysis

Options

N/A

 

The transient analysis is set up as follows. The total number of steps is 200. The time step is 30 second.

Therefore, the temperature distributions for 6000 seconds are solved.

Tab

Setting Item

Settings

Transient analysis

Table

Number

Calculation steps

Output steps

Time step [s]

1

200

10

30

 

Initial Temperature

25[deg] *

* This setting is ignored because the initial temperature, which will be set later in each body attribute, is given priority over this setting.

Model

Body Attributes and Materials

Body Number/Type

Body Attribute Name

Material Name

1/Solid

VOL1

MAT1

4/Solid

VOL2

MAT1

 

The initial temperature of each body is set as follows.

Body Attribute Name

Tab

Properties

VOL1

Initial Temperature

Specify on Each Body Attribute

Initial Temperature : 100[deg]

VOL2

Initial Temperature

Specify on Each Body Attribute

Initial Temperature : 0[deg]

The material properties are set up as follows:

Material Name

Tab

Properties

MAT1

Specific Heat

0.8×10^3[J/kg/deg]

Density

1000[kg/m3]

Thermal Conductivity

8×10^1[W/m/deg]

Boundary Conditions

The outer boundary condition is set as adiabatic. Therefore this model is isolated thermally from the outer world. The radiation between VOL1 and VOL2 are set in the boundary conditions as follows.

Boundary Condition Name/Topology

Tab

Boundary Condition Type

Settings

RadFace3/Face

Thermal

Body-to-body radiation

Radiation rate: 0.7
Group Number: 1

RadFace4/Face

Thermal

Body-to-body radiation

Radiation rate: 0.5
Group Number : 1

Results

The following graph shows the calculated time variation of the temperatures of VOL1 and VOL2.

The temperatures of the two bodies are converging gradually.