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

Actuator disc in 2d

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 15, 2012, 06:21
Default Actuator disc in 2d
  #1
New Member
 
Join Date: Sep 2012
Posts: 3
Rep Power: 4
milidon is on a distinguished road
Hi guys

Does anyone know how i can simulate an actuator disc in autodesk simulation CFD? I mean, how can i add a boundary condition for a pressure drop or pressure jump acroos a line in 2D? Is this possible?


Thank you
milidon is offline   Reply With Quote

Old   October 13, 2012, 16:51
Default
  #2
New Member
 
Join Date: Sep 2012
Posts: 3
Rep Power: 4
milidon is on a distinguished road
ok so how can i do this?
i would be gradefull if you please expain the procedure
milidon is offline   Reply With Quote

Old   January 4, 2013, 12:34
Default RE: Actuator disc in 2d
  #3
New Member
 
Matt Brown
Join Date: Jan 2013
Posts: 17
Rep Power: 4
matt.brown.ae is on a distinguished road
This is accomplished by assigning proper materials. There are also a couple of approaches you can try:

1) For an actuator disk which experiences only drag you can assign a Resistance material. There are several ways to define the properties of this material including constant, free area ratio, friction factor, head capacity and permeability.

My experience is limited to free area ratio. This is exactly what it sounds like. For example, if you had a screen which had some known mesh size and diameter you can calculate the free area ratio which is open area to total area. This directly sets the pressure drop associated with this material. For a good discussion on screens and pressure drops see 'Low-Speed Wind Tunnel Testing' by Barlow, Rae and Pope.

The big problem with this is you can only acquire so much drag for a given free area ratio and actuator size. I had some limited success using this approach to analyze duct performance for ducted wind turbines. This is really more appropriate for modeling things like turbulence screens and honeycomb in wind tunnels.

2) Your other option is Internal Fan/Pump element. Again, there are several ways to define this material you can either specify flow rate (either constant or varying with head) or define a velocity profile which gives velocity vs radius.

We typically use this to model propellers on aircraft when we are concerned about power effects on wings and other structures. I have never used it to model a turbine (i.e. thrust points down stream rather than upstream for a prop). I would be interested to see how that worked out if you try it. The important thing here is to make sure that you define the flow direction properly.

Hope this helps,
Matt
matt.brown.ae is offline   Reply With Quote

Reply

Tags
2d analysis, actuator disc

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



All times are GMT -4. The time now is 22:58.