Hi colleagues, the question is to specialists who have some experience in coal dust combustion. How many representative particles should I set at inlet BC? Is number of particles should be proportional to coal mass flow? Is the number has influence to results (temperature, species fractions, etc.). What number is more robust? CFX Help recommend using more particles to improve convergence. All in all… Big number o small? Pros and contras? What's your opinion? Thanks for responses!

Hi,

each Lagrangian particle represents a certain number of real particles. The larger the number you specify the more accurate the representation will be.

Also, the smaller the number of particles you specify the higher the mass loading for each particle; this can give give problems with convergence because the Lagrangian method generates sources which are introduced into the Eulerian phase.

So, in short, the more particles the better (although this will obviously incur a higher computational cost).

Johnson

I have a big question...

the inlet temperature of air stream, Can it, be environment temperature???