I'm simulating a straw- and gas fired boiler. Is it possible to use two different diameters for the particles (straws) in the Fluent simulation? One volume sphere diameter for particle tracking and area sphere diameter for (surface) combustion.

I've tried to make an UDF for this case, but I haven't succeeded yet. If anyone has a suggestion how to solve this problem, I would like to hear from you.

S. Berg

Haven't tried - but you might be able to scale the apparent reaction rate so that it has the same effect as considering a different sized particle. Of course the mass transfer resistance may not account for this.

There's probably others, but that might be a good simple starting point.

Greg