DPM simulation convergence problem
 

Hi users,

I am trying to model the flow of pulverised coal (dilute phase vol frac < % 10) in a rectangular duct with bend using DPM in FLUENT. I have a convergence problem to be tackled.

In my simulation I both monitored the residuals and velocity profile at the exit and velocity profile did not converged. I got the same behaviour for each strategy i tried below. I also checked max. DPM concentration in the domain for vol. frac. < %10 condition and it is satisfied. Stochastic tracking was enabled. Both particle tracking and flow are treated steady. Realizable k-epsilon was used with full buoyancy. Flow field simulation without interaction with particles converges very well.

Strategies tried (ref: http://www.bakker.org/dartmouth06/engs150/15-dpm.pdf)
– Closer coupling between dispersed and continuous flow:

• Increase underrelaxation for discrete phase.
• Decrease number of continuous phase calculations between trajectory
calculations to less than three.
• Reduce underrelaxation factors for continuous phase.

– Decoupling of dispersed and continuous flow:

• Reduce underrelaxation factor for discrete phase.
• Increase number of continuous phase calculations between trajectory
calculations to more than fifteen.

Any recommendation will be appreciated.

Thanks.

is this just particle transport or also combustion?

istanbulda nerden?

Two way coupling in DPM
 

Hi All,

Could anyone tell how 2-way coupling in DPM simulation is achieved? I have solved the continuous flow field and then created the DPM injection. Is it by lowering the URF for DPM source terms and interaction number between continuous phase and discrete phase?

A suggestion will be highly appreciated.

Regards,