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-   -   CEL Particle Mass/Diameter (http://www.cfd-online.com/Forums/cfx/98536-cel-particle-mass-diameter.html)

papteo March 13, 2012 09:33

CEL Particle Mass/Diameter
 
Hi

Does anyone know how I can define the Particle Mass or Particle Diameter using CEL language??

I know that the variable Particle Diameter exists, but when I am using for example to calculate the Mass of each particle depending on the Diameter

Mp=Solid.Density*pi*4/3 [kg]* Particle Diameter^3

I get the message: the following unavailable variable:Particle Diameter

Thank you very much in advance!

papteo March 14, 2012 04:40

Does anyone know? I would be really grateful if someone could answer today to my question, as there is only a short time left for the project!

ghorrocks March 14, 2012 06:05

Is particle mass a variable which is already available? Then you do not need to calculate it.

papteo March 14, 2012 06:18

HI ghorrocks,

Thank you very much for your answer, but as far as I know ( i am not that expert with CFX) there is no variable for particle mass available in pre processing. I need the mass of the particle because I am trying to simulate the cooling of metal slag particles and we want to have a ratio between the glassy particles (quicker cooled down) and the crystalline particles (slower cooled down).

ghorrocks March 14, 2012 06:30

Have you read the CFX reference guide? It has a list of available variables. It says the variable you are looking for is <Particle type>.Total Particle Mass so it appears you have the wrong variable name. It also suggests these variables are only available in post processing.

But why do you need this? Why don't you define different material properties to both types of particle and then CFX will handle the temperature?

papteo March 14, 2012 07:23

Thanks again for the answer!

As I said I had a llok at the reference guide and I found that is possible to use this variable in Pre Particle Diameter ! But when I am doing that I get the message: the following unavailable variable:Particle Diameter

I cannīt define two different materials, because I want to evaluate the opereration of a dry slag granulator. I want to see if we can achieve with our current geometry the necessary ratio of 95% glassy particles.

ghorrocks March 14, 2012 17:20

The reference guide says the format for the variable is <particle type>.Particle Diameter, not just particle diameter by itself. And it says these variables are only available in post processing anyway so that does not help much if you want them in the solver.

Quote:

I cannīt define two different materials, because I want to evaluate the opereration of a dry slag granulator.
I do not follow the logic of that comment. If you have particles with different properties then you define them as different materials and have both types of particles present in the simulation.

papteo March 14, 2012 17:32

Thx again for the answer!

As I said at the beginning I have the slag particles with various diameters and I want to find out if the 2 meters of the test rig are adequate to cool down all the particles (no matter what diameter) in 0,5 s in order to have as I said above 95% glassy particles . The properties - thermal conductivity,density (more or less the same), Cp- for both end products (glassy + crystalline) are the same!

Leave that, do you have any idea how I can define the particle mass or Diameter in Pre??

Thank you very much

ghorrocks March 14, 2012 17:52

This thread seems to be going round in circles....

The documentation says you cannot access these variables in Pre or the solver. They are only available during post processing.

I suspect if you need to access them in the solver you need to use user fortran.

But you appear to be trying to do stuff which is already done by CFX in the particle heat model, you just need to define particles with the different properties of the different particle types. And properties goes beyond density and Cp, it also includes shape factors, radiation properties etc - if there is a cooling speed difference between these two types of particles some property is causing it.


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