[Twix]

Hi,
I’m 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]

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

[Twix]

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 don’t have experience in that kind of simulation so I can’t help in details.
Regards

[jmjohansen]

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