[Patryk]

Let's say there is a closed aluminum cube. The cube is filled in 1/5 with water and in 4/5 with air . The deck of the cube is a source of the heat. The surface of the cube is constantly cooled. The water in it evaporates, traveles to the surface, gets cooled, condensates and drops down (some kind of a heat pipe).
I want to simulate it with FLUENT.

Questions:
Which model of phases is appropriate(VOF,Eulerian,DPM,Mixture model)? How manage with mass transfer from liquid phase to gasous and vice versa? How simulate heat transfer in this case?
Thank you in advance,
Patryk

[xiaobingwill]

Hi I'm doing similar modeling, can u tell me how did you do this simulation in the end?: Thanks

[Junphy]

I am working on this simulation right now, mixture is perfect I think, the result is better than other models. U need to wright some UDFs to realize the phase change.

[xiaobingwill]

Hi Junphy,

Is it OK for you to share your UDF with me? I got stuck with condensation, and my results with evaporation is not that good. Can you please help me with this?

My email is zhangxiaobinghust@gmail.com

Thanks a lot!

Originally Posted by Junphy

I am working on this simulation right now, mixture is perfect I think, the result is better than other models. U need to wright some UDFs to realize the phase change.

[arunt]

Hey,
I am working on a similar problem but I am focusing on the evaporation behavior alone. The mixture model seems to work fine and as for the UDF, if you have the fluent UDF manual, you can refer it and get on it on your own. Also, you will have to patch water and vapor regions at t=0. For some reason, I cannot patch them and the vapor volume fraction seems zero always. Anyway, the mixture model will be the correct multiphase physics for your problem.

Arun.

[navid2]

Originally Posted by arunt

Hey,
I am working on a similar problem but I am focusing on the evaporation behavior alone. The mixture model seems to work fine and as for the UDF, if you have the fluent UDF manual, you can refer it and get on it on your own. Also, you will have to patch water and vapor regions at t=0. For some reason, I cannot patch them and the vapor volume fraction seems zero always. Anyway, the mixture model will be the correct multiphase physics for your problem.

Arun.

hi
i'm working on evaporation of a single water droplet in a square computational field that is included static air. can u help me about settings of ansys fluent for this problem?
any helps is appreciated.

[CFD-fellow]

Hi
With AnsysFluent its not needed to write udf.It has the mass transfer equations for evaporation and condensation.
These kinds of simulations are really hard to be handled by commercial codes.

[6863523]

Hi CFD-fellow,
I tried the evaporation and condensation mechanism of transient VOF model in FLUENT14.5, but the result is not good, as the phase fraction always change with time and in the final, either the liquid turned in to vapor or vapor turned into liquid. the problem is in the vapor domain, liquid shoud not exist vise verse. I did not interpret/compile any UDFs. At the initial of the simulation, I patched liquid in liquid domain and vapor in vapor domain.
Have you worked the simulation out? Would you please give me some hint? email:1612955572@qq.com
Thank you in advance.
Regards,
Bill

[shahid nadeem]

Originally Posted by 6863523

Hi CFD-fellow,
I tried the evaporation and condensation mechanism of transient VOF model in FLUENT14.5, but the result is not good, as the phase fraction always change with time and in the final, either the liquid turned in to vapor or vapor turned into liquid. the problem is in the vapor domain, liquid shoud not exist vise verse. I did not interpret/compile any UDFs. At the initial of the simulation, I patched liquid in liquid domain and vapor in vapor domain.
Have you worked the simulation out? Would you please give me some hint? email:1612955572@qq.com
Thank you in advance.
Regards,
Bill

Dear did you got the results kindly share the steps with me

[shahid nadeem]

Originally Posted by xiaobingwill

Hi Junphy,

Is it OK for you to share your UDF with me? I got stuck with condensation, and my results with evaporation is not that good. Can you please help me with this?

My email is zhangxiaobinghust@gmail.com

Thanks a lot!

Hello did you got the UDF and if yes kindly share with me at snadeembe@gmail.com

[shahid nadeem]

Originally Posted by Ahmed Alkaisi

Hi all,
* Can anyone tell me which model will be perfect for water evaporation-condensation in a close or open system within Fluent environment, please?
* Is it VOF, Eulerian or Mixture Model? and
* How many phases should I chose 2 ( water and air)
or 3 ( water, air and mixture)?
Answer me please
Many thanks all
Yours, Alkaisi
ahmedalkaisi82@gmail.com

VOF OFfcourse

[ram_call]

VOF is not suitable when phases are interpenetrating. Is is better to use it when boundary between phases is sharp as like open channels (water - air)

As far as in know, older versions of Fluent dont have phase change icon. it is better to use Ansys Fluent versions.

[Ahmed Alkaisi]

Hi all
Firstly, from my experience vof model is the best and the easiest way to deal with evaporation- condensation multiphase problem.
Secondly, do you have any update on your simulation?
Regards

Sent from my SM-G900I using CFD Online Forum mobile app

[Tonoy Mondol]

Originally Posted by Patryk

Let's say there is a closed aluminum cube. The cube is filled in 1/5 with water and in 4/5 with air . The deck of the cube is a source of the heat. The surface of the cube is constantly cooled. The water in it evaporates, traveles to the surface, gets cooled, condensates and drops down (some kind of a heat pipe).
I want to simulate it with FLUENT.

Questions:
Which model of phases is appropriate(VOF,Eulerian,DPM,Mixture model)? How manage with mass transfer from liquid phase to gasous and vice versa? How simulate heat transfer in this case?
Thank you in advance,
Patryk

have you done the problem? I want your code for an idea related to evaporation condensation

[violin000]

Originally Posted by Tonoy Mondol

have you done the problem? I want your code for an idea related to evaporation condensation

The problem I am facing now is that after adding UDF, the gas phase will not increase. Do you solve it? Could you share your code? 603570326@qq.com

[jeet verma]

Originally Posted by violin000

The problem I am facing now is that after adding UDF, the gas phase will not increase. Do you solve it? Could you share your code? 603570326@qq.com

i am also facing the sane type of problem can you please send me your code at jeet.vrm18@gmail.com

[soumitra2102]

I am using evaporation-condensation model. I also tried the Mass rate Linearization UDF available in Fluent UDF guide. But I am not able to see the considerable liquid vapor fraction.

My case is tube flow inlet at 240C @ 3 MPa water vapor. Tube wall is isothermal @100C. At exit pressure drop is 7.25KPa (experiment) with complete condensation to liquid phase.

I am getting the pressure drop right, but temperature profile significantly lower than the experimental.

Can somebody suggest me something on this.
my email is soumitra2102@gmil.com

Thank You.

[Jassu]

hello sir, can you please help me simulating a single water droplet evaporation in static air surrounding.
my mail : aman.mec1721@yahoo.com

[Jassu]

Originally Posted by Ahmed Alkaisi

Hi all
Firstly, from my experience vof model is the best and the easiest way to deal with evaporation- condensation multiphase problem.
Secondly, do you have any update on your simulation?
Regards

Sent from my SM-G900I using CFD Online Forum mobile app

hello sir, can you please help me simulating a single water droplet evaporation in static air surrounding.
my mail : aman.mec1721@yahoo.com