CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Discrete Phase Model, outlet mass flow rate does not fit

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree2Likes

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 3, 2015, 02:52
Default
  #21
Member
 
Eduardo Tola
Join Date: Aug 2015
Location: Madrid/Haifa
Posts: 50
Rep Power: 7
edu_aero is on a distinguished road
Finally, I am using udf =), it a an upgrade that everyone has to do!!

I have been having a look, and the macro that you told me is perfect to calculate my goal (P_FLOW_RATE).

However I am having two problems:

1-. The one that it seems to be easy. I don't know how to make a loop all over the particles in order to calculate the average flow rate.

2-. The one that it is a little more complex. I don't know how to implement the last funtion only to the particles that crosses a determinated surface in a determinated time. I thought about implementing a if statment checking every face ID with 'Lookup_Thread(domain, ID)'. Is there a easier way?
__________________
Having fun with CFD =)
edu_aero is offline   Reply With Quote

Old   September 3, 2015, 06:00
Default
  #22
Member
 
Eduardo Tola
Join Date: Aug 2015
Location: Madrid/Haifa
Posts: 50
Rep Power: 7
edu_aero is on a distinguished road
I have found the function begin_particle_cell_loop(p,c,t). But it does not work for me.

///////////////////////////////////////////////////////////////////////////////////////
#include "udf.h"
#include "dpm.h"

DEFINE_ADJUST(sum_flow_rate, domain)
{
int z=0;
real sum=0;
cell_t c;
Thread *t;
Particle *p;
begin_c_loop(c, t)
{begin_particle_cell_loop(p,c,t)
{
z=z+1;
sum=sum+P_FLOW_RATE(p);
//fprintf (fp,"%d %g %g \n",z,P_DIAM(p),P_MASS(p));
}
end_particle_cell_loop(p,c,t)
}
printf("SUM OF TOTAL FLOW RATE OF PARTICLES [Kg/s]%s\n",sum/z );
end_c_loop(c, t)
}
///////////////////////////////////////////////////////////////////////////////////////


1.- While running, Fluent shows me the following error:
'structure reference not implemented' for the line were
'begin_particle_cell_loop(p,c,t)' is written'


2-. And to calculate that on a surface, would it be just adding:
///////////////////////////////////////////////////////////////////////////////////////
int ID=(Number of surface);
Thread *thread = Lookup_Thread(domain, ID)
///////////////////////////////////////////////////////////////////////////////////////

I don't think that (2-.) would work, but then I don't know how to do it

Thank u very much in advance!!
__________________
Having fun with CFD =)
edu_aero is offline   Reply With Quote

Old   September 17, 2015, 02:42
Default
  #23
New Member
 
Unnikrishnan T P
Join Date: Sep 2015
Location: Chennai, India
Posts: 27
Rep Power: 7
unnikrishnan is on a distinguished road
Hi, I am sorry if this is not of ur interest. In my steady dpm simulation, no of particles is less than no of parcels. Is this posssible?
And edu_aero, can u provide some details of ur solution? ie ur case, no of parcels, Total no of particles, and total no of iterations?pls? (From the summary from reports in Fluent postprocessing) Im facing some serious problems thats why...
unnikrishnan is offline   Reply With Quote

Old   September 17, 2015, 04:03
Default
  #24
Member
 
Eduardo Tola
Join Date: Aug 2015
Location: Madrid/Haifa
Posts: 50
Rep Power: 7
edu_aero is on a distinguished road
Quote:
Originally Posted by unnikrishnan View Post
Hi, I am sorry if this is not of ur interest. In my steady dpm simulation, no of particles is less than no of parcels. Is this posssible?
And edu_aero, can u provide some details of ur solution? ie ur case, no of parcels, Total no of particles, and total no of iterations?pls? (From the summary from reports in Fluent postprocessing) Im facing some serious problems thats why...
'Real'_N_of_particles=N_Parcels x N_Particles
By real number of particles I mean the total number of particles. In general the information that you get from Fluent is the average information of particles in a parcel. In general, you cannot access the information of particles.

Parcel=Group of paticles wih similar conditions. Fluent gives you the information of the mean
And the number of particles per parcel can be constant or change, so it can be that N of particles is less than N of parcel.

Now, I cannot provide you the information but later I will try to upload it here
__________________
Having fun with CFD =)
edu_aero is offline   Reply With Quote

Old   September 17, 2015, 05:51
Lightbulb Case
  #25
New Member
 
Unnikrishnan T P
Join Date: Sep 2015
Location: Chennai, India
Posts: 27
Rep Power: 7
unnikrishnan is on a distinguished road
Im sorry. no need to provide ur information.
Here are few lines from the summary i got...
Total number of parcels : 3304
Total number of particles : 8.998298e+02
Total mass : 1.817365e-04 (kg)
Overall RR Spread Parameter : 1.526257e+01
Maximum Error in RR fit : 3.362975e-01
Overall RR diameter (D_RR): 9.943840e-04 (m)
Maximum RMS distance from injector : 4.432617e-01 (m)
Maximum particle diameter : 1.000000e-03 (m)
Minimum particle diameter : 2.424513e-04 (m)
So the second line is the no of particles per parcel ri8? (Anyway it's a floating number, just to confirm)
unnikrishnan is offline   Reply With Quote

Old   September 17, 2015, 06:47
Default
  #26
Member
 
Eduardo Tola
Join Date: Aug 2015
Location: Madrid/Haifa
Posts: 50
Rep Power: 7
edu_aero is on a distinguished road
Quote:
Originally Posted by unnikrishnan View Post
Im sorry. no need to provide ur information.
Here are few lines from the summary i got...
Total number of parcels : 3304
Total number of particles : 8.998298e+02
Total mass : 1.817365e-04 (kg)
Overall RR Spread Parameter : 1.526257e+01
Maximum Error in RR fit : 3.362975e-01
Overall RR diameter (D_RR): 9.943840e-04 (m)
Maximum RMS distance from injector : 4.432617e-01 (m)
Maximum particle diameter : 1.000000e-03 (m)
Minimum particle diameter : 2.424513e-04 (m)
So the second line is the no of particles per parcel ri8? (Anyway it's a floating number, just to confirm)
I think that it is the average of particles per parcel. You can get the information and check it in:

Results -> Graphics and Animations -> Particle Tracks
Now select the injection, tick in Reoorting type Current positions and report to file
Then export the file and check the number of particles per parcel and you will know if it is correct
__________________
Having fun with CFD =)
edu_aero is offline   Reply With Quote

Old   September 18, 2015, 01:51
Default
  #27
New Member
 
Unnikrishnan T P
Join Date: Sep 2015
Location: Chennai, India
Posts: 27
Rep Power: 7
unnikrishnan is on a distinguished road
I had the report taken earlier and the average no of particles per parcel is around 0.4
I did the particle tracking with "colour by: particle number per parcel" in the dialogue box. And I saw that the colour scale was varying between 0.15 and 11.7. Maximum of 11.7 particles per parcel only? How is that possible??
unnikrishnan is offline   Reply With Quote

Old   September 18, 2015, 04:31
Default
  #28
Member
 
Eduardo Tola
Join Date: Aug 2015
Location: Madrid/Haifa
Posts: 50
Rep Power: 7
edu_aero is on a distinguished road
Quote:
Originally Posted by unnikrishnan View Post
I had the report taken earlier and the average no of particles per parcel is around 0.4
I did the particle tracking with "colour by: particle number per parcel" in the dialogue box. And I saw that the colour scale was varying between 0.15 and 11.7. Maximum of 11.7 particles per parcel only? How is that possible??
It doesn't make sense, parcel number has to be a natural number. The only one than can be a real number is the average.

Also number of particles per parcel has to be more than one
__________________
Having fun with CFD =)
edu_aero is offline   Reply With Quote

Old   September 18, 2015, 06:53
Default
  #29
New Member
 
Unnikrishnan T P
Join Date: Sep 2015
Location: Chennai, India
Posts: 27
Rep Power: 7
unnikrishnan is on a distinguished road
Have you tried plotting particle tracks with "colour by: Particle number in parcel" ??
If yes, what range does it vary in?? Please reply it's important

Also my second question is, there are many options in the colour by box in particle track dialogue box. Out of these they have the options like colour by particle mass and color by parcel mass. How are they gonna colour these large no of particles in the stream
unnikrishnan is offline   Reply With Quote

Old   February 3, 2020, 08:38
Default Particle Summary
  #30
New Member
 
Aizh
Join Date: Jan 2020
Posts: 3
Rep Power: 3
aizhanmardiyeva is on a distinguished road
Hi, I'm working with DPM injections.
1) Exactly, used surface case, and i chose inlet where 4018 surfaces. But i can not control the number of particles. I'm using unsteady DPM.
My questions:
How i can control the number of particle?
2) When i look to summary there are shown that
Total number of parcels : 120458
Total number of particles : 4.855374e-06
How number of particle could be non integer number?
What is parcel mean?
What is the relationsheap between particle and parcel
3) When i look to the Particle Mass Concentration there are shown results in -15 th degree.
aizhanmardiyeva is offline   Reply With Quote

Reply

Tags
discrete phase model, dpm, fluent 15, injection, mass flow rate

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Plotting mass flow rate at outlet for transient simulation Rakib Fluent Multiphase 4 September 5, 2015 23:46
[swak4Foam] mass conservation of solid phase violated when using groovyBC with twoPhaseEulerFoam xpqiu OpenFOAM Community Contributions 8 June 17, 2015 02:08
Split Mass Flow Rate in ANSYS CFX ashtonJ CFX 2 July 9, 2014 03:08
Low Mixing time Problem Mavier CFX 5 April 29, 2013 00:00
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32


All times are GMT -4. The time now is 04:55.