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Author Topic: Modify scale on Pyrosim and soot yield  (Read 10262 times)

Swissi

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Modify scale on Pyrosim and soot yield
« on: March 21, 2011, 04:33:38 am »

Hi everyone,
I'm coming again with questions!

I have two problems with my calculations :

- The first is with the scale on the smokeview view. For example, the scale shows me the maximum soot contentration that I have in my room : 100 mg/m3. My client wants me to change the scale to prove that there is nothing at 120 mg/m3. How can I do that?

- The second thing is the soot yield. I've defined a burner without reaction, and the client wants to know the soot yield. Where can I find it (and change it?).

Thanks a lot,
Laure from Switzerland
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Charlie Thornton

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Re: Modify scale on Pyrosim and soot yield
« Reply #1 on: March 21, 2011, 08:19:29 am »

The options to set the min/max values on the legend are in the File/Bounds Settings dialog. It looks like you can set min/max for Plot3D and Slice data in that way.

As for soot yield, the FDS manual tells me that the default is 0.01 kg/kg. It's under the Byproducts tab in the Reactions dialog. You can set it explicitly. Smokeview shows the soot as smoke, but I don't know how you'd measure it quantitatively. I think you could just say it's 0.01 though.
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Swissi

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Re: Modify scale on Pyrosim and soot yield
« Reply #2 on: March 23, 2011, 05:17:23 am »

Hi Charlie,
Thanks a lot for your help. You're giving me wonderful advices!
I will try for the scale and check for the smoke.
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Swissi

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Re: Modify scale on Pyrosim and soot yield
« Reply #3 on: April 13, 2011, 03:24:46 pm »

Hi everyone,

I've again a question : in my country you have to give the surfaces where a soot density reachs a certain level (when generating slices)
For example my limit concentration of soot in a room is 40 mg/m3. I would like to calculate the surfaces where the concentration is more than that value.
Is it possible to do that? Or do I have to do it by hand?
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Bryan Klein

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Re: Modify scale on Pyrosim and soot yield
« Reply #4 on: April 14, 2011, 09:34:32 am »

I am not exactly sure what you mean by 'surface' in a slice, but I will give you two options and hopefully one of them is what you are looking for.

1) Isosurfaces of Soot Density, In the PyroSim 'Output' menu, there is an 'Isosurfaces...' option.  In the 'Animated Isosurfaces' dialog scroll down until you see the row with the Quantity of '[Extra Species: soot] Density', click the checkbox to the left of this quantity.  Then, in the contour values cell next to the Quantity label, enter '4.0E-5' (don't add the quotes).  This will instruct FDS to create an isosurface where the soot density is at 40 mg/m^3 (0.00004 kg/m^3).  This will not be indicated just on the slice contour, but will show this bounding surface throughout the domain.  If you want to add another isosurface at a higher concentration, let's say at 50mg/m^3, then in the Contour Values cell you should enter '4.0E-5; 5.0E-5' with the values separated by a semi-colon.  You can add as many values as you want to this cell, and each value will be represented by a different isosurface in smokeview.
To see the isosurfaces in Smokeview, just Load the Isosurface data and watch it animate over time.

2) Indicate on a slice plane where a certain value is located.  To do this, load the slice for soot density, and then click in the color-bar to the right.  You will see that where you clicked will turn black and a value will be indicated next to it.  Click and drag the black mark up or down the color-bar until the value next to it is 0.04 (*10^-3).  You will see in the slice black everywhere that the concentration is 40 mg/m^3.

I have attached a couple of images showing the Soot Density slice with the 0.04 values marked in black. Then with the isosurface (magenta) and the slice marked in black so that you can see that the isosurface intersects the slice contour where the black color is marked.  And a final image looking down the plume, showing that the isosurface only marks where the concentration is as indicated in the Contour Values cell.  Think of the isosurface as an animated boundary where everything outside of it is less than the value, and everything inside of it is greater than the value, and in this case the value is 40 mg/m^3.

I hope this helps,
-Bryan Klein
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Jfm

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Re: Modify scale on Pyrosim and soot yield
« Reply #5 on: October 19, 2012, 02:02:12 pm »

Hey Guys,

I was wondering if I define a new reaction and only alter the soot yield value under byproducts would this automatically apply this information to a burner surface I have in the project or do i need to specify to use it or add it somehow?

Thanks
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Bryan Klein

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Re: Modify scale on Pyrosim and soot yield
« Reply #6 on: October 19, 2012, 03:04:59 pm »

Hey Guys,

I was wondering if I define a new reaction and only alter the soot yield value under byproducts would this automatically apply this information to a burner surface I have in the project or do i need to specify to use it or add it somehow?

Thanks

The soot yield is determined by the global gas phase combustion reaction.  You do not need to define it elsewhere.

Best Regards,
-Bryan Klein
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