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

Pressurewave from explosion

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 19, 2002, 09:03
Default Pressurewave from explosion
  #1
André
Guest
 
Posts: n/a
Dear Fluent users,

Has anyone of you got information for me about modeling the pressurewave occuring after an explosion? We do not want to simulate the explosion itself, but only the pressure produced by it.

Many thanks in advance.
  Reply With Quote

Old   June 19, 2002, 13:27
Default Re: Pressurewave from explosion
  #2
Evan Rosenbaum
Guest
 
Posts: n/a
Please clarify your question. Do you want to know how to specify a pressure pulse in FLUENT, or how to determine the pressure pulse that would result from a specific explosion type/size?
  Reply With Quote

Old   June 25, 2002, 02:52
Default Re: Pressurewave from explosion
  #3
André
Guest
 
Posts: n/a
Dear Evan,

The first one is the case: we want to specify a pressure pulse to design equipment for releasing the pressure. But the information we have concerning the explosion is limited so information about pressure pulses for different types of explosion is welcome aswell. People at Fluent allready indicated that patching in a (very)high pressure in a small area would be a way to model this.

Thanks in advance.
  Reply With Quote

Old   June 25, 2002, 13:14
Default Re: Pressurewave from explosion
  #4
Evan Rosenbaum
Guest
 
Posts: n/a
Andre,

The pressure pulse will be a sharp (nearly linear) pressure rise fom ambient to the peak pressure followed by a slower pressure drop back to a low pressure (neglecting any blast-wave reflections). The final pressure may be lower than the pre-blast pressure, depending on your exact conditions.

If you geometry allows, you may be able to use a pressure inlet in the model and specify a time-varying pressure spike. If not (i.e., explosion within a tank of vapor or similar) you can patch the pressure directly into some cells.

Evan
  Reply With Quote

Old   June 25, 2002, 22:06
Default Re: Pressurewave from explosion
  #5
steven
Guest
 
Posts: n/a
hi,all as i know,pressure is assumed to be constant in the premixed turbulent combustion.but pressure can be variant in the case that gas/air is ignited in the tube? Can that quietly gas/air in the tube may be ignited at the end of tube be modeled by premixed turbulent combustion or species transport eqution? thank you sincerly

  Reply With Quote

Old   June 26, 2002, 03:03
Default Re: Pressurewave from explosion
  #6
steven
Guest
 
Posts: n/a
hi, i'm simulating gas explosion in the tube ,one end of tube is close,and another end is open,gas/air is premixed before mixture is ignited.then quietly gas/air is ignited in the tube which end is close ,this case can be modeled by fluent species reaction or premixed turbulent combustion? thank yousincerly
  Reply With Quote

Old   June 26, 2002, 03:06
Default Re: Pressurewave from explosion
  #7
steven
Guest
 
Posts: n/a
hi,all i'm simulating gas explosion in the tube ,one end of tube is close,and another end is open,gas/air is premixed before mixture is ignited.then quietly gas/air is ignited in the tube which end is close ,this case can be modeled by fluent species reaction or premixed turbulent combustion? thank you sincerly
  Reply With Quote

Old   June 26, 2002, 10:30
Default Re: Pressurewave from explosion
  #8
Lanre
Guest
 
Posts: n/a
Yes. You'll need to use the the finite-rate model using either the segregated solver or the coupled solver for your detonation problem.
  Reply With Quote

Old   June 26, 2002, 22:12
Default Re: Pressurewave from explosion
  #9
steven
Guest
 
Posts: n/a
Dear Landre:

thank you!

because gas/air mixture is so small in my problem,and L/D(tube)is so small,it belongs to deflagration case.in order to simulate the case of spark ignition, i patchs pressure and temperature in a small cells,but it often wasn't coverging,can you tell me why ? in addition,it seems that fluent's three combustion model must have the velocity,doesn't it? thank you in advance steven
  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
help for simulation of explosion in deep water richard FLUENT 1 May 19, 2012 12:42
How to simulate an explosion in a tube? tp9180188 FLUENT 0 September 18, 2009 11:10
Crank Case Explosion Manoj Kumar CFX 1 April 16, 2007 18:26
Crank Case Explosion Manoj Kumar FLUENT 0 April 16, 2007 06:32
explosion using laminar flame model imburse CFX 0 August 3, 2001 10:08


All times are GMT -4. The time now is 15:13.