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FLAIR Tutorial 9: Fire-spray in a compartment

This example provides step-by-step instructions on how to activate GENTRA module, which solves the dispersed phase equations using Lagrangian methods and how to load and define the spray-head object for the simulation of fire extinction. In-Form is used to define the transient fire source which is the function of time and the concentration of the water vapour. The geometry of the case is shown in the figure below.

The size of the compartment is 2.8m long x 2.8 m wide x 2.2 m high. A sprinkler is mounted at the ceiling of the middle of the compartment. A fire source is located on the floor facing the sprinkler. There is a wall on the right with a door to the open space.

The simulation starts with a growing fire source before the water spray starts when the spray link temperature exceeds 50C. The entire simulation lasts for 120 seconds.

Setting up the model

Start FLAIR with the default mode of operation

Resizing the domain

To activate the physical models

a. The Main Menu panel

b. add the spray-head

c. add the fire source

d. create the wall with a door

The wall is made of three blockages.

e. add the wall on the high-Y side

f. add the wall on the low-Y side

This wall is made by the duplicating method.

g. add the wall on the low-X side

h. add the floor

i. add the ceiling

This is made by the duplicating method.

j. add the openings

These objects will provide the boundary conditions to the open space.

k. To set the grid numbers and to solver parameters

Variable MH2O TEM1
LINEAR 0.3 0.25
MAXINC 0.5 10

Running the solver

To run the PHOENICS solver, Earth, click on 'Run', then 'Solver', then click on 'OK' to confirm running Earth. 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.

Viewing the results

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'.