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

total pressure change in a pipe flow

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 5, 2002, 20:16
Default total pressure change in a pipe flow
  #1
Im
Guest
 
Posts: n/a
hi everybody. I have been solve pipe flow with orifice. It's very simple problem. The pipe size is L=50m, D=1.0m. It has orifice at L=10m. As everybody knows, the recirculation region occured right after orifice. Because of these recirculating flow, the total pressure dropped suddenly. Now, My problem is that. The average total pressure at around orifice is lower than outlet average total pressure. Is it possible ? As I know, The static pressure at recirculation region is possibly lower than outlet pressure. Decreased static pressure can be increased as dynamic pressure decrease. but the total pressure never can increase without any additional energy. What is wrong? The solution of fluent or my thought that the total pressure never can increased without any addtional energy. If my idea is wrong, please let me know the mechanism of total pressure gain. thanks in advance.
  Reply With Quote

Old   February 6, 2002, 09:46
Default Re: total pressure change in a pipe flow
  #2
hervé
Guest
 
Posts: n/a
Make sure that you are using the so-called "mass-weighted" averaging.

If not, try it, you should see a decrease in the so-averaged total pressure.
  Reply With Quote

Old   February 6, 2002, 12:50
Default Re: total pressure change in a pipe flow
  #3
Amadou Sowe
Guest
 
Posts: n/a
What fluid material are you using?
  Reply With Quote

Old   February 6, 2002, 19:07
Default Re: total pressure change in a pipe flow
  #4
Im
Guest
 
Posts: n/a
I tried all kinds of average method. vertex, facet, mass weighted etc... As change averaging method, the magnitude of total pressure changed, but there is no change in the tendency.
  Reply With Quote

Old   February 6, 2002, 19:09
Default Re: total pressure change in a pipe flow
  #5
Im
Guest
 
Posts: n/a
I used air. I just change the density and viscosity. density = 0.82kg/m^3, and viscosity = 0.1cp
  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
Maintaining Static Pressure at Fluid Flow Inlet cdevalve FLUENT 3 January 14, 2012 00:11
Boundary Conditions : Total Pressure or Velocity Gearb0x OpenFOAM Running, Solving & CFD 2 February 28, 2011 21:18
Pipe Flow - Pressure Drop Daniel L FLOW-3D 2 December 10, 2010 04:23
Total pressure in a laval nozzle Sohail Ahmed FLUENT 0 May 19, 2004 05:28
Hydrostatic pressure in 2-phase flow modeling (long) DS & HB Main CFD Forum 0 January 8, 2000 15:00


All times are GMT -4. The time now is 04:20.