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

Pressure BC for combustion chamber

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 19, 2009, 12:29
Default Pressure BC for combustion chamber
  #1
New Member
 
Giuki Cael
Join Date: May 2009
Location: Belgium/The Netherlands
Posts: 13
Rep Power: 17
Giuki is on a distinguished road
Dear all,

I have some trouble understanding all the parameters for setting up pressure boundary conditions in Fluent.

I have a combustion chamber with annulus to simulate. At this stage cold flow is considered. I'm using velocity inlet or mass flow inlet at the moment under standard operating conditions.

I would like to simulate the chamber under the right pressure. Which would mean the flow entering the annulus at my inlet BC should be under a pressure of approx. 41.6 bar. I want to achieve a pressure drop between 4-5% over my chamber. Let's say for now a pressure drop of 2 bar.

So now in Fluent I can change:

Operating pressure
Pressure inlet: Gauge pressure
Initial/supersonic gauge pressure
Pressure outlet: Gauge pressure

I know that the total pressure is equal to the gauge pressure added with operating pressure. And that by initial/supersonic pressure the static pressure is meant. But that doesn't help me much in setting the right values.

I've tried setting operating pressure at 39.6 bar and setting the Gauge pressure at my inlet at 2 bar and 0 gauge at my exit BC. I have doubts whether this represents the physical situation. Does anybody has an idea how I should set them right and why?

Thank you!
Giuki is offline   Reply With Quote

Old   July 19, 2011, 11:35
Default
  #2
New Member
 
Join Date: Aug 2009
Posts: 5
Rep Power: 17
aruv is on a distinguished road
Hi Giuki,

I am stuck with the same kind of problem...

My settings for the combustion chamber (simple cylinder) :

Air inlet BC: mass flow inlet
gas inlet BC: mass flow inlet
outlet: pressure outlet, gauge pressure = 0.
the operating pressure was set to 5 bar (its the air inlet pressure)
steady state, species transport, cold flow ...

with the above settings fluent gives out following results for Absolute pressure:
outlet: 5bar
Air inlet: 4,6 bar
Gas inlet: 4,7 bar... as u can see the outlet pressure is higher than the inlet pressure..

Could u help me ...
aruv 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
Neumann pressure BC and velocity field Antech Main CFD Forum 0 April 25, 2006 02:15
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 22:02
what the result is negatif pressure at inlet chong chee nan FLUENT 0 December 29, 2001 05:13
Hydrostatic pressure in 2-phase flow modeling (CFX4.2) HB &DS CFX 0 January 9, 2000 13:19
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 22:03.