CFD Online Logo CFD Online URL
Home > Forums > CFX

Modeling a Pelton distrinbutor

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

LinkBack Thread Tools Display Modes
Old   December 11, 2009, 11:32
Question Modeling a Pelton distrinbutor
New Member
Join Date: Sep 2009
Posts: 3
Rep Power: 10
Bynn is on a distinguished road
Hey all!

I'm writing my project at my uni at the moment and I'm trying to simulate the flow in a pelton distributor with CFX. I've done experiments and obtained the static pressure on 6 different places and I'm trying to find the head-loss through the distributor.

In my model I have simple outlets without the nozzles as these are not what I'm interested in. I've specified inlet pressure and outlet velocity through the "nozzles". My problem is the choice of turbulence model, I've tried with a bunch but I haven't found any clue to what kind of modle is the best for me.

Another question I have is about the post-processing of my simulation. I've created planes where I measure the static pressure and compare the head through the turbine with the results from the measurements. I've been using the "ave" function for pressure and velocity on the planes, but someone said that I should use the "areaAve" function instead since this takes into account the size of the nodes. Problem is that the shape of the head-loss matches my experiments when I use the "ave" function, but not when I use the "areaAve" function. I might be going at it wrong, but I wanna know what you guys think.


Last edited by Bynn; December 11, 2009 at 17:50.
Bynn is offline   Reply With Quote

Old   December 13, 2009, 06:18
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 13,852
Rep Power: 107
ghorrocks is a jewel in the roughghorrocks is a jewel in the roughghorrocks is a jewel in the rough
My problem is the choice of turbulence model
If I was you I would just use SST. If you feel like creating work for yourself I would run k-e as well and compare the difference - in this case probably very little. I suspect the turbulence model is not affecting your results much so your choice of model is not too important.

To get average pressures you should use the areaAve function for exactly the reason you describe. To get average velocities you should use the massflowAve function.
ghorrocks is offline   Reply With Quote


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
May Focus Area: Turbulence Modeling Jonas Larsson CFD-Wiki 0 May 2, 2006 11:48
Modeling Flow/Saturation/Absorption in Fibers Gene Dougherty Main CFD Forum 0 June 6, 2003 14:49
Solid Modeling Chris Main CFD Forum 10 July 2, 2002 07:12
CFD Modeling of Two-phase Flow in Small Dia.Tubes Eric Poindexter Main CFD Forum 2 September 22, 2000 09:21
Extrusion Modeling Elliot Schwartz Main CFD Forum 1 September 11, 1998 19:08

All times are GMT -4. The time now is 18:59.