CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > Siemens

PISO 50 with discarge coeff down???

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

LinkBack Thread Tools Search this Thread Display Modes
Old   January 24, 2008, 20:00
Default PISO 50 with discarge coeff down???
Posts: n/a
Hi everybody,
when I simulate a Diesel ICE I get these results with a discarghe coeff Cd = 0.825: when I use underela = 0.7, scalar underela = 0.5 and drnp = 0.35 I get maximum PISO = 12 from the time of start of injection (SOI) til the end of combustion.
Instead, when I use Cd = 0.7 I get PISO > 50 many times at the start of combustion...and PISO < 12 after the start of the combustion...what is a possible reason in your opinion???
I've see the when the Sauter Mean Diameter drop under 10 micron (when Cd go down velocity rise up...) I get PISO > 50...but with the Lagrangian approach it should be better that the droplet is much low compared to the cell...where am I wrong?
And also...I've tried to run with time step at 1/10 of the original, also with underela = 0.5, underela of scalar = 0.3 and drnp = 0.1...I always get the same results!
Plase share your ideas!

  Reply With Quote

Old   February 1, 2008, 13:33
Default Re: PISO 50 with discarge coeff down???
Posts: n/a
nobody has any idea about this problem???
  Reply With Quote


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
piso dontknow Main CFD Forum 1 September 21, 2006 09:01
PISO newposter Main CFD Forum 1 February 15, 2006 06:20
Help with PISO Beni Main CFD Forum 0 September 30, 2005 10:02
Inertia Coeff. Sham FLUENT 0 May 1, 2005 23:57
Plot drag coeff,lift coeff VS angle of attack John FLUENT 2 August 29, 2003 13:06

All times are GMT -4. The time now is 08:50.