CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > CFX

Gidaspow model

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 27, 2010, 16:28
Default Gidaspow model
  #1
Member
 
sara
Join Date: Sep 2010
Posts: 33
Rep Power: 6
s_baghalian is on a distinguished road
hi
i am modeling a domain with 2 phases. one phase is water and other phase is dispersed solid. i selected Gidaspow for drag coefficient but it doesn't run and one error occur. when i select Schiller Naumann, program run but its results is incorrect. do you know that why this model don't run with Gidaspow model?
s_baghalian is offline   Reply With Quote

Old   December 27, 2010, 17:34
Default
  #2
New Member
 
pannsave
Join Date: Apr 2009
Posts: 25
Rep Power: 8
pannsave is on a distinguished road
Could you specify the more details of your problem,
What is the solid volume fraction and mean particle size in your case
What was the error ..
pannsave is offline   Reply With Quote

Old   December 27, 2010, 17:46
Default
  #3
Member
 
sara
Join Date: Sep 2010
Posts: 33
Rep Power: 6
s_baghalian is on a distinguished road
yes, of course. volume fraction of sand is 0.73 and mean particle size is 1.28 mm. i selected these options in domain:
maximum packing=0.62
restitution coeff= 0.8
fluid models= inhomogeneous
for particles:
kinetic theory is on.
granular temperature model= algebraic
radial distribution = Gidaspow
turbulence= laminar
solid bulk viscosity,shear viscosity and pressure model= kinetic theory
drag coefficient= Gidaspow
program don't run and no result file error is shown.
do i define other option for remove this error and run it?
do i define minimum volume fraction for it?
s_baghalian is offline   Reply With Quote

Old   December 27, 2010, 19:41
Default
  #4
New Member
 
pannsave
Join Date: Apr 2009
Posts: 25
Rep Power: 8
pannsave is on a distinguished road
Could you check whether your simulation run without an error when kinetic theory model is off and use simple model of gidaspow for solid pressure.

May be problem with the prediction of granular temperature value and check it
Sometimes they may have unphysically large granular temperatures where the regions of low solid particle volume fraction.
so in order prevent this, specify an upper bound for the granular temperature
pannsave is offline   Reply With Quote

Old   December 28, 2010, 01:20
Default
  #5
Member
 
sara
Join Date: Sep 2010
Posts: 33
Rep Power: 6
s_baghalian is on a distinguished road
thank you very much for attention you. yes, i has run it without kinetic theory but results are incorrect.
how i can specify an upper bound for the granular temperature?
s_baghalian is offline   Reply With Quote

Old   December 28, 2010, 04:37
Default
  #6
New Member
 
pannsave
Join Date: Apr 2009
Posts: 25
Rep Power: 8
pannsave is on a distinguished road
There is option for specifying upper bound of granular temperature in Kinetic theory model ie., Maximum granular temperature option
pannsave is offline   Reply With Quote

Old   December 28, 2010, 07:43
Default
  #7
Member
 
sara
Join Date: Sep 2010
Posts: 33
Rep Power: 6
s_baghalian is on a distinguished road
what is the value of it? i don't find its value.
s_baghalian is offline   Reply With Quote

Old   December 28, 2010, 11:26
Default
  #8
New Member
 
pannsave
Join Date: Apr 2009
Posts: 25
Rep Power: 8
pannsave is on a distinguished road
I dont know extactly the range of maximum granular temperature, May be you can look it in the literature

I prefered to give in the range of 0.01 m2/s2

Orlese you try different values to ensure the simulation results are independent of maximum granular temperature
pannsave is offline   Reply With Quote

Old   January 1, 2011, 07:30
Default
  #9
Member
 
sara
Join Date: Sep 2010
Posts: 33
Rep Power: 6
s_baghalian is on a distinguished road
hi
In this model, i turned off kinetic theory, and used Gidaspow model with compact modulus = 100 for solid pressure. Is this model suitable for modeling Water and sediment?
i modeled it inhomogeneous, is it correct or i should model it homogeneous?
s_baghalian is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
question about turbulence model selection and sensitivity karananand Main CFD Forum 1 February 26, 2010 05:41
Centrifugal Pump and Turbulence Model Michiel CFX 12 January 25, 2010 04:20
Problems bout CFD model of biomass gasification, Downdraft gasifier wanglong FLUENT 2 November 26, 2009 00:27
Reynolds Stress model in CFX vs Fluent Tim CFX 1 October 7, 2009 06:19
Grid resolution for full-scale and down scaled model gravis Main CFD Forum 0 October 2, 2009 10:27


All times are GMT -4. The time now is 20:38.