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

DPM mass flow rate

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 6, 2013, 04:53
Default DPM mass flow rate
  #1
Member
 
sajeesh
Join Date: Feb 2013
Posts: 52
Rep Power: 13
sajeesh is on a distinguished road
Hi

During iteration it is showing
Injecting 1 particles with mass 2.72272e-12
this is not mass flow rate
I given mass flow rate as 2.72272 e -9 kg/sec as mass flow rate
In the summery result it is showing number as 3.33468 e-1 what is that..some body in DPM field pls help me

thanking You
Sajeesh
sajeesh is offline   Reply With Quote

Old   May 7, 2013, 03:25
Default
  #2
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 27
RodriguezFatz will become famous soon enough
Let me guess, your time-step is 1.0e-3, right?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   May 7, 2013, 03:49
Default
  #3
Member
 
sajeesh
Join Date: Feb 2013
Posts: 52
Rep Power: 13
sajeesh is on a distinguished road
really thank you for the reply

I was stuck in this problem

I had given a time step of 0.001 seconds.and number of time step as 1 and start and stop injection i given is 0.001 and 300 sec respectively to ensure the presence of particle

Exactly i want to find out the extra hydraulic resistance produced by the presence of one particle in the flow...by measuring the pressure drop difference with particle and without one p[article


Thank you sir pls help me
sajeesh is offline   Reply With Quote

Old   May 7, 2013, 04:07
Default
  #4
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 27
RodriguezFatz will become famous soon enough
You insert 1 particle of mass 2.72272e-12 kg per time step. Your time step is 1.0e-3 s. That gives you a mass flow rate of "2.72272e-12 kg / 1.0e-3 s = 2.72272e-9 kg/s". That's what you want. What is the problem?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   May 7, 2013, 04:35
Default
  #5
Member
 
sajeesh
Join Date: Feb 2013
Posts: 52
Rep Power: 13
sajeesh is on a distinguished road
sir
mass of one particle is volume of particle x density of particle
Diamter of particle is 25 micron
Volume 4/3 pi r^3
density is 998 kg/m3
so the mass i calculated for one particle is 8.181e-15 kg

Then after that
my channel is 2000 um length
Then to cover this distance with flow rate of continous phase 50 ul/min ( oil denisty 840 kg/m3) take nearly 0.003 seconds


Then mass flow rate i calculated as mass of one particle *number of partcicle(1) /0.003 kg/sec

AS you said this makes me wrong


Sir can i know what is meant by number of particle in parcel.A method to set the mass flow rate

I want to further discuss with you can i get your email id

Any way thanks for your replies
sajeesh is offline   Reply With Quote

Old   May 7, 2013, 04:42
Default
  #6
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 27
RodriguezFatz will become famous soon enough
Maybe your confusion comes from the difference of particles and parcels.
Fluent Help (16.12.1.4) says:

For typical applications, the computational cost of tracking all of the particles individually is prohibitive. Instead, the approach for the discrete element method is similar to that of the DPM, in that like particles are divided into parcels, and then the position of each parcel is determined by tracking a single representative particle. The DEM approach differs from the DPM in the following ways:
The mass used in the DEM calculations of the collisions is that of the entire parcel, not just that of the single representative particle.
The radius of the DEM parcel is that of a sphere whose volume is the mass of the entire parcel divided by the particle density.


Also: The mass flow rate of your inlet DPM phase has nothing to do with the size of your domain. It is just "injected mass per time step / time step size".
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   May 7, 2013, 05:46
Default
  #7
Member
 
sajeesh
Join Date: Feb 2013
Posts: 52
Rep Power: 13
sajeesh is on a distinguished road
sir

Its very helpful for me.
During iteration it is showing

I particle tracked 1 particle escaped

at Some time 3 particle tracked 1 escaped ( ie is it mean two particle remain in the domain) Can i say it as a two particle of my specified diameter 25 micron or parcel. If it is parcel please explain me.

some time

At the end of iteration it is showing 1 particle tracked and 1 escaped.So it mean that no particle in the domain.


Sir one more help how can i animate these particle tracking.Movement of partcle with time
In workbench CFD post it is taking only trk files.But how can i get trk file in FLUENT...

Thank you.With out your help i may proceed the mass flow rate calculation with domain time

Thanks
sajeesh
sajeesh is offline   Reply With Quote

Old   May 26, 2020, 09:40
Default
  #8
New Member
 
rawaa
Join Date: May 2020
Posts: 3
Rep Power: 6
rawaa is on a distinguished road
hi
i use steady state and dpm .
i have 30 kg of sand and the time of abrasion is three hours.
how can i calculate the mass flow rate in kg/s if i have im3??
thanks
rawaa is offline   Reply With Quote

Old   May 26, 2020, 09:48
Default can you help me for this question
  #9
New Member
 
rawaa
Join Date: May 2020
Posts: 3
Rep Power: 6
rawaa is on a distinguished road
hi
i use steady state and dpm .
i have 30 kg of sand and the time of abrasion is three hours.
how can i calculate the mass flow rate in kg/s if i have im3??
thanks
rawaa is offline   Reply With Quote

Reply

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
mass flow rate not conserved in turbomachine, interface defined wrong? wildli FLUENT 3 September 15, 2022 12:19
UDF to measure Mass Flow Rate a.lynchy Fluent UDF and Scheme Programming 31 October 4, 2018 14:10
CFX turbo - Mass flow rate Vashishth Patel CFX 7 April 3, 2014 20:33
Mass flow rate of the DPM mass sourse ?? Rhinocao FLUENT 3 January 21, 2011 12:10
mass flow rate error Masood FLUENT 0 May 22, 2005 00:32


All times are GMT -4. The time now is 08:47.