Simulation issues

Francesco R.

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Nov 1, 2023, 6:59:53 AM11/1/23

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Hi all,

I have a problem that I cannot solve in my simulation.

I have an industrial warehouse in which there are 480 square wooden blocks of 1m side with transparent horizontal pvc roofing, the ignition occurs from one of the blocks and there is flame propagation.

I am having problems with the deletion of blocks (I would like the blocks to disappear once burnt out but the option "allow block to burn away" does not work) and I also have problems with some windows not being deactivated by the respective device despite everything being set.

In addition, the reaction (by default, taken from the pyrosim software library) has 'REAC_FUEL' as a reagent but always buy a notice in which everything is associated with nitrogen.

I attach the FDS of the project. (pyrosim file is about 157MB, i cannot attach it due to 24MB limit size)

Simulazione_Modificata.fds

dr_jfloyd

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Nov 1, 2023, 7:40:41 AM11/1/23

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You need to set BURN_AWAY and possibily BULK_DENSITY. See the FDS User's Guide Special Topic: Making Fuels Disappear. Also your RAMP_Q ends at 0. If the integral of the RAMP_Q*HRRPUA/HEAT_OF_COMBUSTION is not greater than or equal to the mass present, the OBST will not get removed.

The REAC_FUEL message is not an ERROR. It is a WARNING. You have not defined any thermophysical properties for your fuel so FDS is defaulting to NITROGEN parameters (see the chapter in the User's Guide on defining species).

Francesco R.

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Nov 1, 2023, 11:45:09 AM11/1/23

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First of all, thank you for your reply.

I am going to set burn away parameter and add bulk density of a block, I have to calculate the integral in order to understand what is going on.

I will launch the simulation and wait the results.

May you tell me something about those pvc on roof that are not be disabled? (PVC is the name of the transparent roof surfaces, the device measures temperature and at 150°C disables these objects)

dr_jfloyd

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Nov 1, 2023, 12:09:37 PM11/1/23

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Are you saying that the DEVC reach 150 C but the obstacles are not removed?

Francesco R.

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Nov 1, 2023, 5:00:45 PM11/1/23

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Only some of them are not removed once the temperature reaches 150 C, most are correctly removed

Francesco R.

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Nov 2, 2023, 4:37:47 PM11/2/23

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I have tried the new settings but there seems to be no removal of the wooden blocks. Is there something I forgot to set or check?

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