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Author Topic: Quantifying HRR & Air Intake Flowrates  (Read 1883 times)

Dapke36

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Quantifying HRR & Air Intake Flowrates
« on: July 02, 2015, 06:24:17 am »

I am modeling an Atrium smoke exhaust system, but using an irregular fuel composition & geometry.  I've gotten myself a little confused on what the total HRR is that I'm putting out, and I'm wondering what is the best device I can use to measure the HRR of the total fire over time.

I'm running a 1x1x1 mesh at the atrium floor, so I have a Flow Measuring Device at Z=0 and Z=1, both LxW the size of the burner vent.  Z=0 is recording a negative value (not surprising, as it's on the burner), but my Z=1 is recording a total output about 400 kW lower than I was expecting.

Is there another measurement device that might better quantify my total HRR over time from the fire?  I see the "Heat Release Rate" device, but I am not sure how to best apply that if appropriate (the fact it is a volume vs a plane gives me pause).

Fire is t2, and I know there is more growth coming, but the curve is not as steep as expected and is leveling off already.

Any suggestions?
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Dave McGill

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Re: Quantifying HRR & Air Intake Flowrates
« Reply #1 on: July 02, 2015, 09:11:56 am »

Hi,

The easiest thing is to check the jobname_hrr.csv file, which is created automatically. If it indicates that you are still getting a lower value than you think you should get, then make sure there is an adequate air supply, and/or try a finer mesh.

Dave
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Dave McGill
firemodel.ca