Week 8 - Natural Convection-II

CHALLENGE:

Build the model as per the following information.

Mesh the model with nonconformal meshing

Solve the problem of natural convection.

MODEL:

1. The model has been created based on the given drawing. and simplified to ICE PAK objects using SpaceClaim.

2. Two grilles have been created in the bottom with direction allowing fluid flow inward.

3. One grille is placed on top with a bigger size to allow hot air to pass out.

4. This principle is based on the natural draft fluid flow due to density variation.

MESHING:

1. The initial mesh has been generated with default settings. and examined for further refinements.

2. Mesh bleeding was observed in the domain so N/C assemblies have been created for the breakers.

3. The mesh type was changed to cartesian inorder to create high-quality elements as all geometries are linear.

4. The above image shows the mesh from XYZ direction. the mesh was finer to capture all physics.

5. The below images show the quality of the mesh elements with a Face alignment of 0.93 and skewness is 0.77.

CASE SETUP:

1. The problem has been solved for the natural convection case.

2. Joules heating is set up for the bus bar with respective given current values.

3. Power dissipation is defined for all breakers.

4. Problem is solved with model-based initialization to get better convergence.

4. The solution residuals show better convergence characteristics. and the solution converged quickly.

POST-PROCESSING:

1. The below image shows the cut plane in the middle of the domain with higher temperature in the top region.

2. The below image shows the temperature contours for all bodies in the domain.

3. The below image shows the particle traces based on velocity magnitude. with a higher velocity value of 64m/s. The grilles position is important for natural convection to occur. and in this case, it is efficient as the temperature of components near inflow grilles is very less.

4. The below image shows the variation plot of temperature from one side of the domain to another side. with the highest temperature is reported in the middle of the domain. and it is very near the inflow grilles.

IMPRESSION:

1. The temperature is very high in incoming bus bars so it is recommended to solve the problem with radiation heat transfer to see changes.

2. It is also recommended to set up another set of grilles in the middle of the cabinet to further improve the heat transfer.