# Release of power in a hollow sphere¶

## Overview¶

The aim of this test case is to validate the following functions:

• Volume heat source

The simulation results of SimScale were compared to the results presented in [TPLV06]. Four mesh cases were considered; linear and quadratic tetrahedrals, linear and quadratic hexahedrals.

Import validation project into workspace

## Geometry¶

Only a portion of a hollow sphere with an internal and external radius of 1 and 2 meters respectively was used for the analysis, as shown in the picture above. Face AECG is the internal face and face BFDH is the external face.

## Analysis type and Domain¶

Tool Type : Calculix, Code_Aster

Analysis Type : Steady-state heat transfer

Mesh and Element types :

Case Mesh type Number of nodes Number of 3D elements Element type Tool type
(A) linear hexahedral 125 64 3D isoparametric CalculiX
(B) quadratic hexahedral 425 64 3D isoparametric CalculiX
(C) linear tetrahedral 1730 7115 3D isoparametric CalculiX
(D) quadratic tetrahedral 11547 6460 3D isoparametric CalculiX
(E) linear hexahedral 125 64 3D isoparametric Code_Aster
(F) quadratic hexahedral 425 64 3D isoparametric Code_Aster
(G) linear tetrahedral 1730 7115 3D isoparametric Code_Aster
(H) quadratic tetrahedral 11547 6460 3D isoparametric Code_Aster

## Simulation Setup¶

Important

All temperature dependent data is given as a function of °C. This also applies for the data in the different simulations on the SimScale platform (although it says K)!

Material:

• isotropic: $$\rho$$ = 1 kg/m³, $$\kappa$$ = 1 W/(m °C), Specific heat $$c$$ = 1 J/(kg °C)

Initial Conditions:

• Initial Temperature $$T_{initial}$$ = 0 °C

Temperature:

• Temperature $$T$$ = 20 °C on face AECG and BFDH

Heat flux:

• Volume heat source on whole volume with $$q_{v}$$ = 100 W/m³

## Results¶

The figure below shows the result of case A with marked temperature values along the edges at distance of 1.25, 1.5 and 1.75 meters from origin.

Comparison of average temperature along the edges at distance of 1.25, 1.5 and 1.75 meters from origin obtained with SimScale and the results presented in [TPLV06]. The Error was calculated with respect to [TPLV06] ¹.

Comparison of the average temperature at distance of 1.25, 1.5 and 1.75 meters from origin [°C]
Distance [m] [TPLV06] ¹ [°C] [TPLV06] ² [°C] Case A [°C] Error [%] Case B [°C] Error [%] Case C [°C] Error [%] Case D [°C] Error [%] Case E [°C] Error [%] Case F [°C] Error [%] Case G [°C] Error [%] Case H [°C] Error [%]
1.25 30.625 30.467 30.471 0.50 30.638 0.04 30.475 0.49 30.625 0.00 30.471 0.50 30.638 0.04 30.474 0.49 30.625 0.00
1.5 32.500 32.346 32.331 0.52 32.498 0.01 32.449 0.16 32.500 0.00 32.331 0.52 32.498 0.01 32.449 0.16 32.500 0.00
1.75 28.482 28.381 28.368 0.40 28.471 0.04 28.401 0.28 28.482 0.00 28.368 0.40 28.471 0.04 28.401 0.28 28.482 0.00