CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLOW-3D

How simulate the aerated flow in spillway using Flow-3D

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 5, 2013, 07:43
Question How simulate the aerated flow in spillway using Flow-3D
  #1
New Member
 
zhj
Join Date: Mar 2013
Posts: 5
Rep Power: 4
Zenvironment is on a distinguished road
Recently,we are simulating the aerated flow in spillway by using Flow-3D, but I have some questions about the models and parameters in the simulation.
Jeff Burnham has said this situation only need three models: air entrainment、density evaluation and drift-flux. I think so, but I can not get the parameters from everywhere.
Who can tell me how define the parameters ?Aeration concentration is very important for me. I will be very happy if you could give me the more details.
My research project planning is about ordinary spillway (Non-stepped). Can you give some advices ?
If you can help me, I would be very grateful !
air entrainment.jpg

density.jpg

drift.jpg
Zenvironment is offline   Reply With Quote

Old   April 6, 2013, 04:54
Default
  #2
Senior Member
 
Saeed
Join Date: Jan 2013
Posts: 177
Rep Power: 4
flow_CH is on a distinguished road
HI
do you simulating a spillway with self aeration or artificial aeration into the aerator ramp? because I have same problem.But i could not access a good guide to simulate that.
i don't know can i simulate spillway with aerator device in flow 3d or fluent?
flow_CH is offline   Reply With Quote

Old   April 6, 2013, 22:54
Default
  #3
Senior Member
 
Jeff Burnham
Join Date: Apr 2010
Posts: 203
Rep Power: 7
JBurnham is on a distinguished road
Those parameters look reasonable. The one that might need calibration is the Air Entrainment Rate Coefficient: it is very cell-size dependent in FLOW-3D versions before v10.1.

The best way to approach it would be to find data for a case that is similar in scale to the one you are going to model. Find the mesh size that you want to use for your case, and with that mesh size, do simple test cases to figure out what the air entrainment rate coefficient should be.

If you have no idea, use 0.5, but the concentration may not be as accurate as you would like. The trend will be correct, and usually depth-of-penetration of the air is pretty reliable as well.
JBurnham is offline   Reply With Quote

Old   April 8, 2013, 22:30
Default
  #4
New Member
 
zhj
Join Date: Mar 2013
Posts: 5
Rep Power: 4
Zenvironment is on a distinguished road
my project is also about aerator device . The documents what I have read almost simulate the solution by Fluent. But my tutor make me use the Flow-3D, I have no idea. How about your project?
Zenvironment is offline   Reply With Quote

Old   April 8, 2013, 22:34
Default
  #5
New Member
 
zhj
Join Date: Mar 2013
Posts: 5
Rep Power: 4
Zenvironment is on a distinguished road
Quote:
Originally Posted by flow_CH View Post
HI
do you simulating a spillway with self aeration or artificial aeration into the aerator ramp? because I have same problem.But i could not access a good guide to simulate that.
i don't know can i simulate spillway with aerator device in flow 3d or fluent?
my project is also about aerator device . The documents what I have read almost simulate the solution by Fluent. But my tutor make me use the Flow-3D, I have no idea. How about your project?
Zenvironment is offline   Reply With Quote

Old   April 8, 2013, 22:51
Default
  #6
New Member
 
zhj
Join Date: Mar 2013
Posts: 5
Rep Power: 4
Zenvironment is on a distinguished road
Quote:
Originally Posted by JBurnham View Post
Those parameters look reasonable. The one that might need calibration is the Air Entrainment Rate Coefficient: it is very cell-size dependent in FLOW-3D versions before v10.1.

The best way to approach it would be to find data for a case that is similar in scale to the one you are going to model. Find the mesh size that you want to use for your case, and with that mesh size, do simple test cases to figure out what the air entrainment rate coefficient should be.

If you have no idea, use 0.5, but the concentration may not be as accurate as you would like. The trend will be correct, and usually depth-of-penetration of the air is pretty reliable as well.
Thank you very much,JBurnham. I think you must be an expert, I read all your replies in the forums. Now we are simulating the spillway on the basis of your idea.
If you have time, can you tell me about the Richard-Zaki coefficient mutiplierAverage particle radius and Volume fraction of phase #2atinversion point in the Drift-flux model.
Thank you !
Zenvironment is offline   Reply With Quote

Old   April 9, 2013, 07:50
Default
  #7
Senior Member
 
Saeed
Join Date: Jan 2013
Posts: 177
Rep Power: 4
flow_CH is on a distinguished road
Quote:
Originally Posted by Zenvironment View Post
my project is also about aerator device . The documents what I have read almost simulate the solution by Fluent. But my tutor make me use the Flow-3D, I have no idea. How about your project?
can you simulate this project in flow3d? if you can then i can do that too.
my problem is injecting air into the air duct. can you simulate that? and can flow3d model the cavity above the offset?
is your project similar to this pic?
see this pic
flow_CH is offline   Reply With Quote

Old   April 10, 2013, 22:25
Default
  #8
New Member
 
zhj
Join Date: Mar 2013
Posts: 5
Rep Power: 4
Zenvironment is on a distinguished road
Quote:
Originally Posted by flow_CH View Post
can you simulate this project in flow3d? if you can then i can do that too.
my problem is injecting air into the air duct. can you simulate that? and can flow3d model the cavity above the offset?
is your project similar to this pic?
see this pic
It's so similar。 In fact, I have given my results to my teacher, he said the result is almost correct, but I must prove the method is right. Our hydraulic model can not get the data of air concentration, so I need to prove my method by myself.
346545_副本.jpg

jkghjbsad_副本.jpg
Zenvironment is offline   Reply With Quote

Old   April 10, 2013, 23:59
Default
  #9
Senior Member
 
Saeed
Join Date: Jan 2013
Posts: 177
Rep Power: 4
flow_CH is on a distinguished road
Quote:
Originally Posted by Zenvironment View Post
It's so similar。 In fact, I have given my results to my teacher, he said the result is almost correct, but I must prove the method is right. Our hydraulic model can not get the data of air concentration, so I need to prove my method by myself.
Attachment 20648

Attachment 20649
Thanks. Can you give me the prepin file of your project.I don't know which software can simulate this situation (flow3d or fluent). I want to know can flow3d simulate the cavity bottom of the offset? with Increasing or decreasing the air rate into the ramp.
Attached Images
File Type: jpg 56.jpg (34.3 KB, 17 views)
flow_CH is offline   Reply With Quote

Reply

Tags
aerated flow

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
About Some Concepts:Laminar flow, turbulent flow, steady flow and time-dependent flow Jing Main CFD Forum 5 March 2, 2013 15:02
interFoam / bubbleFoam to simulate an aerated tank Meratb OpenFOAM Running, Solving & CFD 2 June 9, 2011 07:35
Can 'shock waves' occur in viscous fluid flows? diaw Main CFD Forum 105 November 20, 2009 05:19
solver for simulate droplet flow in microfluidics titio OpenFOAM Running, Solving & CFD 0 October 1, 2009 14:02
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07


All times are GMT -4. The time now is 13:39.