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Author Topic: Numerical Instability + extinguishment by Inert Agent  (Read 2026 times)

wilsonobre

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Numerical Instability + extinguishment by Inert Agent
« on: August 15, 2015, 04:41:38 pm »

Hi everyone,
I'm just trying to model an extinguishment of fire by Inert Gas, IG-55! This is a 30 minutes of simulation in a Data Center (model_06.psm). When i extract my HRR plot, it's showing me that the fire tends to be extinguished, but when I increment my time of simulation to 50 seconds it gives me an error: Numerical Instability!
I've made a simple test and I got a HRR plot that I want (Ext_IG.psm)

I had attached my 2 models and my HRR plot, so if you can help me i really appreciate this
« Last Edit: August 19, 2015, 09:46:09 am by wilsonobre »
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mfrench

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Re: Numerical Instability
« Reply #1 on: August 17, 2015, 01:19:16 pm »

(1) It looks like your fire is ventilation limited; i.e. extinguishing from lack of O2, not from introduction of agent.
(2) You are dumping a large volume of inert gas in without an overpressure vent (compartment is reaching 600,000 Pa).

Are these really the conditions that you are trying to model?
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wilsonobre

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Re: Numerical Instability
« Reply #2 on: August 18, 2015, 01:12:12 pm »

Hi Mr mfrench,Thanks for answer me!
 I was just wondering, but i think that you picked up a wrong model, I had attached two model on my topic,  one that fire is totally extinguished (Ext_IG.psm) and the another model (model_06) that it's is not being extinguished! In the model_06.psm, i've got this kind of plot where the pressure is going always down.
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wilsonobre

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Re: Numerical Instability + extinguishment by Inert Agent
« Reply #3 on: August 25, 2015, 09:06:41 am »

Hey guys say something! I still need help
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