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Author Topic: IGNITION D*  (Read 709 times)

Niklas

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IGNITION D*
« on: June 08, 2018, 05:50:08 am »

Hi,

Can anyone please tell me how to find characteristic diameter, for igniter type fire source (surface temperature 1000c)

thank you,
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jharbold

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Re: IGNITION D*
« Reply #1 on: June 11, 2018, 10:52:26 am »

https://www.utfireresearch.com/fds-mesh
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ankur7680

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Re: IGNITION D*
« Reply #2 on: June 13, 2018, 10:46:28 pm »

but in ignition type of fire source, surface temperature(T "C) is used instead of HRR (kw), then how to give value of 'Q' in D* formula,
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jharbold

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Re: IGNITION D*
« Reply #3 on: June 15, 2018, 02:51:34 pm »

I don't follow.  Surface temperature is not used in this equation - Q dot is.  Further, there is a calculator at the bottom of the page.

Don't get hung up on what the perfect D* value is.  Perform a mesh sensitivity analysis to determine if your mesh size is appropriate.  If you do not know what a mesh sensitivity analysis is, I would recommend that you carefully read the Disclaimer of the FDS user guide and reconsider your use of FDS.
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