Activating fire after some time delay - Tips?

[Nat Ong]

Hi All, 

Not sure if anyone have experience in modelling a delayed fire. My problem is as below:

I would like to start a fire in a building after 5 min wind start blowing,i.e. Yes, i am modelling a wind scenario and would like the study the impact of fire in a turbulent space,under the interference of wind to the building. However, the normal way i prescribe a fire is by calculating the ramping time by using a t2 fire growth (the TAU_Q), see below the example

  

&SURF ID='FIRE',      HRRPUA=500.00,  TAU_Q=-230.90/

Could anyone advise on any FDS build-in functions which will enable me to create the fire after 5min delay and follow a fast t2 growth rate?

Thanks,

Natalie 

[Dave McGill]

Hi Natalie,

Here are a couple of options.

1. Use a control command to have the burner appear 5 minutes into the fire. When it appears it will start it's t^2 growth.
2. Determine a number of representative points to approximate the t^2 growth, then use a ramp feature to have the fire begin growing 5 minutes into the simulation and ramp-up at the desired rate.

Dave

[Mohamed ASSAL]

Hi Natalie,

You can also use this calculator :
http://www.koverholt.com/t-squared-fire-ramp-calculator/

Cheers Mohamed.

2013/1/24, Dave McGill <dwt.m...@gmail.com>:

> Hi Natalie,
>
> Here are a couple of options.
>

> 1. Use a control command to have the burner appear 5 minutes into the

> fire. When it appears it will start it's t^2 growth.

> 2. Determine a number of representative points to approximate the t^2

> growth, then use a ramp feature to have the fire begin growing 5 minutes
> into the simulation and ramp-up at the desired rate.
>
> Dave
>

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