# creating model for pipe system????

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 LinkBack Thread Tools Display Modes
 September 13, 2011, 01:57 creating model for pipe system???? #1 New Member   Join Date: Mar 2010 Location: Thailand Posts: 11 Rep Power: 9 i'm using gambit to create pipe system in the water tank with the airflow inside the pipe. do i have to create volume of pipe and tank or just create two volume of fluid(air and H2O) and set the pipe as wall boundary condition looking for ur advice,thank you

 September 13, 2011, 04:39 #2 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,250 Rep Power: 34 can you post a sketch of your geometry? And how is your domain filled initially with your mediums? __________________ In memory of my friend Hervé: CFD engineer & freerider

 September 13, 2011, 06:03 #3 New Member   Join Date: Mar 2010 Location: Thailand Posts: 11 Rep Power: 9 here is my problem air flow in pipe system in water with the heater on bottom face of tank

 September 13, 2011, 06:56 #4 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,250 Rep Power: 34 where is water? (outside pipes?) I assume you have solid conduction between air and water, right? __________________ In memory of my friend Hervé: CFD engineer & freerider

 September 13, 2011, 08:17 #5 New Member   Join Date: Mar 2010 Location: Thailand Posts: 11 Rep Power: 9 yes,water is outside in the picture is two fluid zone of air and water and i set all air-volume's face except inlet and outlet to be wall do i have to create solid volume of pipe and tank

 September 13, 2011, 08:35 #6 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,250 Rep Power: 34 ok, I am not experienced with this kind of calculations, but I would take a look at the online help >> two sided walls with thermal conditions (http://my.fit.edu/itresources/manual...e253.htm#32911) In this optic, you need to define the surfaces separation between air & water as wall. If you don't do this (and if your splits are correct) then fluent will interpret those surfaces as internal. Then you have two separated domain on which you can set separated fluid domain (fluid1 & fluid2) http://my.fit.edu/itresources/manual...zone_cont_type But be sure your fluid domain are correct (if your delete water domain, it remains air), and if you delete air domain, it remains water domain (with hollow instead of pipes >> enable render option in gambit) __________________ In memory of my friend Hervé: CFD engineer & freerider

 September 13, 2011, 10:26 #7 New Member   Join Date: Mar 2010 Location: Thailand Posts: 11 Rep Power: 9 so fluents will create wall-shadow for my pipe-wall right??? Last edited by keng; September 13, 2011 at 23:22.

 September 14, 2011, 01:33 #8 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,250 Rep Power: 34 it is mentionned in the online-help, yes: "If the wall zone has a fluid or solid region on each side, it is called a "two-sided wall''. When you read a grid with this type of wall zone into FLUENT, a "shadow'' zone will automatically be created so that each side of the wall is a distinct wall zone. In the Wall panel, the shadow zone's name will be shown in the Shadow Face Zone field. You can choose to specify different thermal conditions on each zone, or to couple the two zones" __________________ In memory of my friend Hervé: CFD engineer & freerider

 September 14, 2011, 06:51 #9 New Member   Join Date: Mar 2010 Location: Thailand Posts: 11 Rep Power: 9 thank you very much for ur advice,-mAx- now i'm running it on fluents6.3.26 i set inlet face as pressure_inlet and outlet face as preesure as pressure_outlet for air domain with std k-e solver but some problem is appear in water domain my tank has 1 m height in z-axis and i set the gravity of -9.81m/s2 in z total pressure at bottom of the tank should be density*gravity*height=998.2*9.81*1= 9792.342 Pa or near by right? but my result show aroud 5100 Pa at bottom of the tank and -4500 Pa on top. i set all tank wall to be copper 0.002m-thickness with shell conduction i try to turn on laminar zone in water fluid panel but the result is worst,total pressure is around e+18 Pa how can i fix it? thank you very much again for ur advice Last edited by keng; September 14, 2011 at 11:50.

 September 15, 2011, 03:18 #10 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,250 Rep Power: 34 very quick 'cause I am in vacation... Your pressure difference between inlet and outlet seems to be ok: 5100 - (-4500) = 9600 Pa which are in accordance with hydrostatic. You can also set an operating pressure which is in fact an offset. __________________ In memory of my friend Hervé: CFD engineer & freerider

September 15, 2011, 05:49
#11
New Member

Join Date: Mar 2010
Location: Thailand
Posts: 11
Rep Power: 9
hi max,
im try to patch pressure in solve>initialize>patch to be 4900 Pa which around half of hydrostatic before iteration and the result come good,is that right way to fix it???

Quote:
 You can also set an operating pressure which is in fact an offset.
if i change the operating pressure, is it effect to air domain, i set air-density as ideal-gas and water as piecewiese-linear with temp

THX

 November 14, 2011, 11:10 #12 Member   Join Date: Sep 2011 Posts: 39 Rep Power: 8 For a two sided wall when you want to specify different thermal conditions it looks like there is no heat transfer between the walls. How can you enable heat exchange between a wall and its shadow??

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post ashtonJ CFX 0 February 17, 2011 22:07 Margherita Cadorin CFX 0 October 29, 2008 06:24 Jan CFX 1 October 9, 2006 08:16 Jan NUMECA 0 October 9, 2006 04:30 Jonas Larsson FLUENT 5 March 13, 2000 04:27

All times are GMT -4. The time now is 05:24.

 Contact Us - CFD Online - Privacy Statement - Top