Setting Up Fire Dynamics

Set up the dynamic properties of the fire by selecting the Fire Dynamics tab.



The Turn On Fire Regions list in the upper left lets you tick the checkboxes of regions that represent the fire, including any fire volumes that you may have created in the previous tab.

Select the pressure boundary in the list in the upper right.

If you wish to use an N-spread model, then tick the checkbox.

This makes the fire sources appear in the list, and you can use the buttons to the right of it to change the sequence. Simply select a fire source in the list and click the button to move it up or down within the list.



Select a fire volume from the drop-down list, and do as follows:

  • Specify the maximum simulation time for it.
  • Specify the values for alpha, p, and the HRR start time.
  • Use the radio buttons to select whether you want to specify the limit for Q or for t, and then enter the value.
  • Select another fire volume from the list, if applicable, and repeat the above steps.

The fire and smoke wizard retains your entries for each of the fire volumes.

This wizard also sets up a monitor plot of the heat release rate, which is previewed in the panel.



To control the parameters of this plot, click the Set Graph Parameters button.

You can also tick a checkbox to use the DOM (Discrete Ordinates Method) radiation model. When you activate the radiation model, Simcenter STAR-CCM+ calculates the absorption coefficient of the air and gas mixture [1] as:
Figure 1. EQUATION_DISPLAY
a=0.01, if T<323Ka=0.01+(3.49/377)(T−323), if 323K≤T<700Ka=3.5+(3.5/700)(T−700), if T>700K
(19)

[1]
A.J. Grandison, E.R. Galea, and M.K. Patel. May 2001. "Fire Modeling Standards/Benchmark—Report on SMARTFIRE Phase 2 Simulations", Fire Safety Engineering Group, University of Greenwich, May 2001.