Learning Forum

[TSADEGHI]

Hello all, 

I am simulating spray injection inside a tube using the DPM model. I have considered some planes inside the tube to track particle size distribution along the tube. I have defined relative humidity of 50 % in the inlet and outlet of the tube. Here is my question:

I got the DPM report for the particles that passed the planes inside the tube. However, my total particle mass should be 15 mg while in some planes it is more than 15 mg (i.e., 20 mg). Considering recirculation regions inside the tube, does Ansys track each particle that passes the plane one time? If so, when a particle passes a plane more than one time( trapped in a recirculation region), does Ansys track that particle more than one time? 

As far as I know, Ansys gives all particles a specific particle ID. So if a particle passes a plane more than once, the particle ID repeats in the DPM report? or change? Or does Ansys track it one time? 

Particle size can be changed during the simulation due to the relative humidity (condensation or evaporation). So, even the same particle that passes a plane couple of times can have more than one size or mass. 

I got confused, and any help would be appreciated.

 

Best,

Taha

[Rob]

The report tracks any particle that passes the plane, so in a recirculation zone you'll potentially have a very high tracked mass. 

[TSADEGHI]

Thank you very much Rob for your fast reply. 

Is there any way to eliminate this since it introduces high errors in calculating particle size distribution or total particle mass along the tube? 

 

Another question is, what happens to the particle ID if Ansys tracks the same particle that passes the plane (whether it is the first time, second time, or tenth time)? Does it give a new unique particle ID to each particle that passes the plane? Or the particle ID will be the same? 

 

Best,

Taha

[DrAmine]

You can write a routine to kill these particles which are undergoing this behavior: you need to formulate a smart criteria for that. Or you write your own DPM Sampling routine and exclude these particles based on theier ID and velocities-

[Rob]

The track/parcel ID is the same so you could filter based on that. Look at the last column in the output file. 

[TSADEGHI]

Thank you all. That worked pretty well.