RE: Effect of sprinklers on Pyrolysis

[Arulnambi Palani]

Dear Sir,

Currently, I am performing fire simulation with sprinklers to study how sprinklers are affecting heat release rate of the fire.

One such case involves complex pyrolysis model (material decomposition). For the sake of testing my model, I have set the material's REFERENCE_TEMPERATURE=20°C and varied the ambient temperature (20°C, 60°C and 80°C). A sample .fds file is also attached.

At the end, I have compared the heat release rate (HRR) of the simulation with and without sprinkler (please see attached). The observation is that, for ambient temperature 20°C, the difference between the results are not big or maybe, even the values are same. But, as the ambient temperature is increased, one can observe the effect of sprinklers on HRR.

I would like to know why such behavior is seen and the concept behind it. Please explain me or kindly point me in the right direction.

I have tired in the internet, but I couldn't find answers to my question. Thank you.

Best regards,

Arul.

[Kevin]

No, this is completely wrong. The REFERENCE_TEMPERATURE is not 20 C. It is the temperature at which the materials decomposition rate is at its peak. Read the User's Guide and Verification Guide sections on pyrolysis.

[dr_jfloyd]

If you are going to be using FDS to do research applications you need to spend some time analyzing results and not just rely upon the user community to do your work.  

You have not mentioned whether or not you have

-looked at how much water is impacting the surface

-looked at how the surface temperature changes between the different runs

-looked at how heat feed back to the surface has changed between runs