Variable Heat capacity of solid particles

prX411 · July 12, 2013, 06:09

Hi Guys!

I am running a steady state simulation in CFX 14.0 of a free jet in which solid particles are injected. The model uses the Particle Transport Solid i.e Eulerian-Lagrange model which works since my particle volume fraction is low in the whole domain (less than 0.005).

The results are ok but so far i have just analysed the results for differents meshs...for that purpose i chose a constant value for the heat capacity of the particles. Since I have found the mesh now that is fine enough I now want to improve the particle properties of the solid particles.

Now i tried to different ways to add a temperature dependent behaviour for the heat capacity of the particles: An expression that was fittet to experimental results as well as an user function with interpolation data.

In both cases the solver returns an error at the beginning that only Nasa Polynomials, Zero pressure Polynomials or canstant values are allowed:

After I read the manual about these polynomials I think this is no solution for me since i have solid particles --> no gas constant

Does CFX just "acts" like there is a gas constant for the solid material and if yes how can i add a zero pressure polynom for my particles?

Thanks!

Regards

prX411 · July 12, 2013, 10:53

Ok

i added the Zero pressure polynom now to my modell...but the solver doens't start and returns an error. The Particles enter the domain with a temperature of 300 K and attain temps. over 2700 K so i choose the a range of 300 to 3000 Kelvin for particle temps.

I used excel to fit the experimental results and divided the coefficients by the specific gas constant although that doenst really exist for my solid particles.

So there is only the question left if CFX just "acts" like there is a gas constant for the solid material or not.

Does anyone know another way to fix that problem?

July 12, 2013, 06:09	Variable Heat capacity of solid particles	#1
prX411 New Member S.F Join Date: Jun 2013 Posts: 4 Rep Power: 13	Hi Guys! I am running a steady state simulation in CFX 14.0 of a free jet in which solid particles are injected. The model uses the Particle Transport Solid i.e Eulerian-Lagrange model which works since my particle volume fraction is low in the whole domain (less than 0.005). The results are ok but so far i have just analysed the results for differents meshs...for that purpose i chose a constant value for the heat capacity of the particles. Since I have found the mesh now that is fine enough I now want to improve the particle properties of the solid particles. Now i tried to different ways to add a temperature dependent behaviour for the heat capacity of the particles: An expression that was fittet to experimental results as well as an user function with interpolation data. In both cases the solver returns an error at the beginning that only Nasa Polynomials, Zero pressure Polynomials or canstant values are allowed: After I read the manual about these polynomials I think this is no solution for me since i have solid particles --> no gas constant Does CFX just "acts" like there is a gas constant for the solid material and if yes how can i add a zero pressure polynom for my particles? Thanks! Regards

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July 12, 2013, 10:53		#2
prX411 New Member S.F Join Date: Jun 2013 Posts: 4 Rep Power: 13	Ok i added the Zero pressure polynom now to my modell...but the solver doens't start and returns an error. The Particles enter the domain with a temperature of 300 K and attain temps. over 2700 K so i choose the a range of 300 to 3000 Kelvin for particle temps. I used excel to fit the experimental results and divided the coefficients by the specific gas constant although that doenst really exist for my solid particles. So there is only the question left if CFX just "acts" like there is a gas constant for the solid material or not. Does anyone know another way to fix that problem?