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

Can FLUENT model flashing liquids?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 12, 2005, 12:55
Default Can FLUENT model flashing liquids?
  #1
SWK
Guest
 
Posts: n/a
hi,

I want to model flashing liquid inside a control valve. For FLUENT 6.2, i know that there is two models available for modelling mass transfer which is the cavitation model and the unidirectional mass tranfer model. At first i thought i can do it with cavitation model but it seems that the pressure profile is not really correct as the outlet pressure cannot go below the vapor pressure as it should be for flashing service.

Anyone out there can give me a help? Btw anyone know where to download Fluent 6.2 User Guide?

Thank you in advance.

Regards,

SWK
  Reply With Quote

Old   December 12, 2005, 14:14
Default Re: Can FLUENT model flashing liquids?
  #2
Alec Eiffel
Guest
 
Posts: n/a
hi

Our research group developed a flashing flow model using UDFs and UDS equations for FLUENT. Unfortunately its under a confidentiality agreement so cant share the code. You will need to write your own code for FLUENT to model flashing liquid as FLUENTs cavitation model is not suitable as you have said.

best of luck!
  Reply With Quote

Old   December 12, 2005, 20:24
Default Re: Can FLUENT model flashing liquids?
  #3
SWK
Guest
 
Posts: n/a
Thank you Alec.

I try to use the UDF but when i try to interpreted it, it show parse error. Anything i can do for this in order to proceed? Btw when it show line 1: parse error, from which line we start to count from the code? start from DEFINE ...?

Regards,

SWK
  Reply With Quote

Old   December 13, 2005, 12:57
Default Re: Can FLUENT model flashing liquids?
  #4
Alec Eiffel
Guest
 
Posts: n/a
It counts from the very first line of the c file. Have you included the #include "udf.h" line at start of UDF?
  Reply With Quote

Old   December 13, 2005, 22:55
Default Re: Can FLUENT model flashing liquids?
  #5
SWK
Guest
 
Posts: n/a
yup... i have that line. you mean start to count from include udf.h?
  Reply With Quote

Old   June 17, 2017, 01:21
Default
  #6
New Member
 
Khaled hussain
Join Date: Nov 2016
Posts: 3
Rep Power: 3
khaledhussain is on a distinguished road
Hi .. could anyone send me the UDF for flashing, I am trying to use fluent to expect fluid flashing on CD nozzle, please I need your help, I tried the euilerian evaporation condensation model and the real gas model but I couldnt find any realistic results in terms of pressure and velocity profiles.

Sent from my SM-N9005 using CFD Online Forum mobile app
khaledhussain is offline   Reply With Quote

Old   June 20, 2017, 13:04
Default
  #7
New Member
 
李弘扬
Join Date: Jan 2012
Posts: 12
Rep Power: 8
lihongyang0 is on a distinguished road
I think you could simply your case. What the saturation do you want to simulate?
lihongyang0 is offline   Reply With Quote

Old   June 21, 2017, 19:01
Default
  #8
New Member
 
Khaled hussain
Join Date: Nov 2016
Posts: 3
Rep Power: 3
khaledhussain is on a distinguished road
Thanks for your reply ! simulation is aimed to expand the compressed liquid water from 50 C (4 degrees below saturation temp) down to 6 C at saturation condition. The eulerian evap.cond. model gave me a result for flashing (as the water is successfully evaporated) but not accurate as the mixure velocity supposed to increase at diversion section after nozzle thoat because of supersonic cond. but this wasnt happen. also the pressure profile is totally different than experimental resuls. Please advise !

Sent from my SM-N9005 using CFD Online Forum mobile app
khaledhussain is offline   Reply With Quote

Old   June 21, 2017, 21:45
Default
  #9
New Member
 
李弘扬
Join Date: Jan 2012
Posts: 12
Rep Power: 8
lihongyang0 is on a distinguished road
I am using cavitation model to simulate flashing. In some nozzles, the results agrees well with the experiment. How about changing your software? Use 17.0 or higher?
lihongyang0 is offline   Reply With Quote

Old   June 22, 2017, 01:17
Default
  #10
New Member
 
Khaled hussain
Join Date: Nov 2016
Posts: 3
Rep Power: 3
khaledhussain is on a distinguished road
I tryed the cavitation model but the problem that the pressure at diversion section is increased above saturation regardless of the pressure ratio, so bubells are getting collapse and condesate back (it make sense for cavitation). I am using 16.2 and didnt check the higher ver., do you think the problem of flashing is resolved in 17 ?!

Sent from my SM-N9005 using CFD Online Forum mobile app
khaledhussain is offline   Reply With Quote

Reply

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
Seeking Macroscopic Particle Model in Fluent bzhang7 FLUENT 1 October 26, 2017 03:54
Water subcooled boiling Attesz CFX 7 January 5, 2013 04:32
Fluent 12 k-w SST turbulence model DarrenC FLUENT 0 December 13, 2009 09:33
two turbulence model in fluent duaiduaihu FLUENT 1 August 26, 2009 19:39
Covert Star-CD model to FLUENT Lam Siemens 6 June 24, 2003 20:21


All times are GMT -4. The time now is 13:37.