Radiation Effect on a Dome-Shaped building, ANSYS Fluent CFD Training

Radiation Project Description

The present problem simulates the heat transfer inside a mosque by ANSYS Fluent software. In the present case, it is assumed that heat transfer takes place in two modes of convection and radiation. In fact, the building’s indoor heating source is powered by solar energy and a heat source used on the ground floor of the mosque. The heat transfer between the sidewalls of the mosque, the roof of the mosque and its dome is done with the free airflow of the surrounding environment with a temperature of 309 K and the heat transfer coefficient of 10 W.m-2.K-1.

Radiant heat transfer is also carried out on the sidewalls, roof, and dome of the mosque due to the radiation of sunlight and assuming an absorption coefficient of 0.8 for the surfaces. Therefore, the radiation model is used to simulate the present problem. Since it is assumed that the material of the mosque building and the glass used on it has a high absorption coefficient, the Rosseland method is suitable. The solar load model has also been used to apply the effect of solar radiation. Also, the heat source used in the floor of the mosque, in the amount of 30 W.m-2, applies a thermal heat flux to the floor of the mosque, assuming a thickness of 20 cm for the floor.

Since the main purpose of the issue is to investigate the heat transfer within the mosque, there is no need for inlet and outlet boundary conditions.

Geometry & Mesh

The geometry of the present model is three-dimensional and has been designed using Design Modeler software. Model geometry has a simple structure. The mosque building consists of a dome, sidewalls, floor, roof, and several interior columns. Here is the geometry of the building.

We do the meshing of the present model by ANSYS Meshing software. The mesh type is unstructured and the element number is 674066. The following figure shows a view of the meshing.

Assumption

We assume several assumptions for the present simulation:

• The solver is Pressure-Based.
• Simulation has investigated both fluid behavior and heat transfer.
• The simulation is Steady-State.
• The effect of the gravity on the model is equal to -9.81 m.s-2 along the Z-axis.

Radiation CFD Simulation

The following is a summary of the steps for defining a problem and its solution:

Models (Radiation)
k-epsilon	Viscous model
standard	k-epsilon model
standard wall function	near wall treatment
Rosseland			Radiation model
solar ray tracing	solar load model
on			Energy
Boundary conditions (Radiation)
Wall	Bottom
30 W.m-2	heat flux
0	solar absorptivity
Wall			Roof, dome and side walls
309 K	free stream temperature	convection
10 W.m-2.K-1	heat transfer coefficient
0.8	solar absorptivity
Solution Methods (Radiation)
SIMPLE	Pressure-velocity coupling
second order	pressure		Spatial discretization
second order upwind	momentum
second order upwind	energy
first order upwind	turbulent kinetic energy
first order upwind	turbulent dissipation rate
second order upwind	density
Initialization (Radiation)
Hybrid	Initialization method

Radiation Results

After the solution process, two-dimensional and three-dimensional contours related to temperature, pressure, velocity, as well as two-dimensional and three-dimensional velocity vectors were obtained. The two-dimensional contours are drawn in two sections, YZ, and XZ, passing through the center of the mosque building.

You can obtain Geometry & Mesh file and a comprehensive Training Movie that presents how to solve the problem and extract all desired results.