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Twix November 16, 2011 05:21

Particle Radiation Interaction
 
Hi,
Iím modeling tangentially fired boiler and everything is fine, my solution is converged but when I try to include particle radiation my solution starts diverge. My turbulence model is standard k-e and radiation model is DO. I use species transport, volumetric reactions and eddy dissipation. To inject particles to the domain I use DPM and for particle combustion kinetics/diffusion-limited model. My question is: what is the best way to include particle in radiation process? I tried to increase values of Particle Emissivity and Particle Scattering Factor but number higher than 0.05 cause solution divergence while recommended values are respectively 1 and 0.9.
I would be grateful for any suggestions.

Regards

xrs333 November 20, 2011 08:29

Hi, Twix,
How did you define the saturate pressure of the droplet material? Did you use temperature dependent function? It is very important.

Twix November 21, 2011 05:52

Hi xrs333,
I use wet combustion mode to include moisture contained in coal particles and by default saturation vapor pressure is set as piecewise-linear temperature dependent. In my case moisture content is small so impact on simulation will be also small (it delay devolatilization initiation a little and add some H20 vapor). If you modeling droplet vaporization or liquid fuel combustion it is value used to obtain driving forces of evaporation process but I donít have experience in that kind of simulation so I canít help in details.
Regards

jmjohansen September 23, 2014 03:48

solved?
 
Did you find a solution to this? I am experiencing the same difficulties when modeling biomass devolatilization in laboratory furnaces.


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