FLAIR Tutorial 6: A fan mounted at the boundary of a cabinet

This case shows how to activate the "Fan Operating Point" option for a single fan mounted at the boundary of a cabinet as shown below.

Setting up the model

Start FLAIR with the default room

The FLAIR VR-Environment screen should appear, which shows the default domain with the dimensions 10mx10mx3m.

Set the cabinet size

Change the X size to 0.5m

Change the Y size to 0.5m

Change the Z size to 0.7m

Adding objects to the cabinet

a. add the top vent

X: 0.3 m

Y: 0.2 m

Z:0.0 m

X: 0.1 m

Y: 0.15 m

Z: 0.7 m

b. add the fan object:

X:0.2 m

Y:0.0 m

Z:0.3 m

X: 0.15 m

Y: 0.0 m

Z: 0.2 m

c. add the first chip

X:0.05 m

Y:0.07 m

Z:0.02 m

X: 0.15 m

Y: 0.15 m

Z: 0.35 m

d. add the second chip by duplicating CHIP1

X: 0.3 m

Y: 0.15 m

Z: 0.35 m

e. add the PCB

X:0.3 m

Y:0.3 m

Z:0.01 m

X: 0.1 m

Y: 0.1 m

Z: 0.34 m

Now we have 5 objects listed in the 'Object management' dialog box as shown below

To activate the physical models

a. The Main Menu panel

To activate 'K-E' turbulence model

FLAIR always solves pressure and velocities. The temperature is also solved as the default setting.

The 'Models' page of the Main Menu.

to activate 'Fan operating point' option

0.  8.
25.  6. 
50.  4. 
75.  2.
100  0. 

To set the grid numbers and to solver parameters

in X-direction to 20 cells

in Y-direction to 20 cells

in Z-direction to 30 cells

You can click on the 'Mesh toggle' button on the main control panel to view the grid distribution on the screen as shown below.

IXMON = 9; IYMON = 9; IZMON = 18

Running the Solver

To run the PHOENICS solver, Earth, click on 'Run', then 'Solver', then click 'OK' to confirm running Earth. Select 'YES to all' on Geometry Replacement Window. These actions should result in the PHOENICS Earth monitoring screen.

As the Earth solver starts and the flow calculations commence, two graphs should appear on the screen. The left-hand graph shows the variation of solved variables at the monitoring point that was set during the model definition. The right-hand graph shows the variation of errors as the solution progresses.

To the end of the calculation, the monitoring display would be as shown below.

Viewing the results

Final result: Operating point data
System mass flow rate: 6.2970E+01 kg/h
Fan Name: FAN Fan Type: FAN1
FAN mass flow rate:    1.1642E+02 kg/h
FAN volume flow rate:  9.7896E+01 m^3/h
FAN velocity:          2.4494E-01 m/s
FAN pressure drop:     1.6825E-01 Pa 

Saving the case

Once a case has been completed, it can be saved to disk as a new Q1 file by 'File - Save working files'. The Q1 and associated output files can be saved more permanently by 'File - Save as a case'.