CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Heat transfer problem at nucleate boiling (http://www.cfd-online.com/Forums/fluent/78238-heat-transfer-problem-nucleate-boiling.html)

MrStuebb July 15, 2010 17:11

Heat transfer problem at nucleate boiling
 
Hello,

Im trying to simulate nucleate boiling of an ammonia-water-mixture by fluent 6.3. in a pipe with turbulent flow and eulerian multiphase model. Therefor Im using the udf of the "Nucleate Boiling"-Tutorial by Fluent. For this udf I defined two boundary conditions for the interior wall, one for the solid side (wall) and one for the fluid side (wall-shadow). The mesh on the fluid side got a very fine boundary layer.

My Problem:
The solution doesnt show any heat transfer between wall and fluid. Im sure that material data, entered in fluent and udf, are correct because I tried to iterate the tutorial data with original udf on my mesh in the same way the tutorial do. But no heat transfer occurs.

If there is someone with an idea for solving my problem Im thankful for telling me.

best regards

mrstuebb

deep_seak August 13, 2010 11:57

Boiling model
 
Hi. I am also trying to simulate the same tutorial case and having the same problem. I even tried to model the same geometry as the tutorial's one and also import the original mesh file in gambit and then exported it again and run the solution. But in all the above cases no heat transfer occured. If you find any answer then please send me at deep_seak@yahoo.com

MrStuebb January 7, 2011 12:59

Hello,

late, but better than never :)

try to change the wall-shadow and wall-shadow-shadow boundaries of the pipe wall with each other. When I remind correct, it was the failure in my case.

hamdy February 27, 2011 10:56

Sorry, but i have similar problem. Could you plz send me the boiling tutorial on my mail: hamdy.abotaleb@yahoo.com

Thanks

majidsa6 May 21, 2011 01:34

hi my friend,

if u send for me your udf code i can help u

because i should run it in fluent and i answer to u for your error

Ghalebsater June 12, 2011 22:08

Hello guyz, Is there a UDF for 3d or the given 2d udf from the tutorials will work on any 3d model. Any idea??

raoudha April 4, 2012 07:57

Quote:

Originally Posted by MrStuebb (Post 267536)
Hello,

Im trying to simulate nucleate boiling of an ammonia-water-mixture by fluent 6.3. in a pipe with turbulent flow and eulerian multiphase model. Therefor Im using the udf of the "Nucleate Boiling"-Tutorial by Fluent. For this udf I defined two boundary conditions for the interior wall, one for the solid side (wall) and one for the fluid side (wall-shadow). The mesh on the fluid side got a very fine boundary layer.

My Problem:
The solution doesnt show any heat transfer between wall and fluid. Im sure that material data, entered in fluent and udf, are correct because I tried to iterate the tutorial data with original udf on my mesh in the same way the tutorial do. But no heat transfer occurs.

If there is someone with an idea for solving my problem Im thankful for telling me.

best regards

mrstuebb

hello mrstuebb

Im also trying to simulate two phase flow of an ammonia-water-mixture by fluent in vertical tubes, my problem is how to define the materiel properties of water-ammonia mixture, could you help pleaaaase

thank a lot
raoudha

MrStuebb April 4, 2012 14:18

Hi,

as far as I can remember we calculated the material properties according to the volume rates of water and ammonia in the mixture and entered it as one phase into FLUENT. In FLUENT you have the possibility to determine the material properties as a function of temperature.

The properties of vaporization of the mixture were determined in a UDF-function, related to the temperature and pressure of the mixture.

I hope I this will help you!

raoudha April 11, 2012 08:23

thank you very much i'll try this, hope it works
best regards

raoudha April 25, 2012 12:05

dear MrStuebb

i'm still trying to write the UDF for ammonia-water mixture properties, could you pleaaaaaaaaaaase help me with en example cause it's the first time i deal with UDfs and it seems a little complicated, would you help pleaaase, my mail is " garma_raoudha@yahoo.fr "

with lot of thank

ahmedalneama December 18, 2014 15:35

Sorry, but i have similar problem. Could you please send me the boiling tutorial on my mail: ahmad_alniema@yahoo.com

Thanks


All times are GMT -4. The time now is 13:46.