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-   -   evaporation and condensation simulation for help (http://www.cfd-online.com/Forums/fluent/50663-evaporation-condensation-simulation-help.html)

Wei Shao February 24, 2009 08:13

evaporation and condensation simulation for help
 
I am new in Fluent. Can anyone tell me if Fluent can simulate evaporation and condensation of water in a pipe? I would appreciate it if anyone can help me! Thanks a lot!


Pablo February 24, 2009 16:51

Re: evaporation and condensation simulation for he
 
of course it can, read fluent user's guide

Wei Shao February 25, 2009 08:55

Re: evaporation and condensation simulation for he
 
Really? Can Fluent simulate two phase flow in a pipe and track the interface between liquid and vapor and discontinuity through the interface?


Pablo February 25, 2009 09:44

Re: evaporation and condensation simulation for he
 
see VOF model

Wei Shao February 25, 2009 09:50

Re: evaporation and condensation simulation for he
 
Thnanks a lot!

Wei Shao February 27, 2009 12:23

Re: evaporation and condensation simulation for he
 
I am really not familiar with Fluent, Could you please recommend some references which did similar problem?

Thanks a lot!

radiation.boy November 28, 2011 01:26

Use evaporation condensation model in Fluent 12.1 ... u will see it when u activate mixture model and in phases click on interaction button... there u vl open a page with many tabs .. click on mass tab and u vl open a window in which u can give number of mass transfer mechanisms ... by defualt it vl be zero change it to one and den select from mass transfer mechanism condensation evaporation model and den give ur saturation temperature and frequency of evaporation and condensation datz all...

Maria Jesus February 2, 2012 19:16

hi.

I'm new in fluent.

i'm working in a model with water evaporation, but i can't understand the "saturation temperature" idea, because the temperature change a lot when i use it... :(

Could someone help me with that concept, please.

Thanks.

radiation.boy February 9, 2012 01:16

Quote:

Originally Posted by Maria Jesus (Post 342532)
hi.

I'm new in fluent.

i'm working in a model with water evaporation, but i can't understand the "saturation temperature" idea, because the temperature change a lot when i use it... :(

Could someone help me with that concept, please.

Thanks.

U have tio analyze the temprature and pressure decrement rate and then accoding to these value u have to define a udf for saturtion tempteraure... if u dont know the temp and press decreamemnt rate then u have to assume it ok

foolstop May 17, 2012 21:13

hi, did you use the vof model successfully simulate the process of condensation? what's your results? and any condensation phenomenon occur?

Dariush53 December 28, 2012 11:36

Evaporation Boundary Condition
 
In my work I need to simulate evaporation for boundary condiation.

I am not familiar with fluent completely.

I have one questaion about setting Evaporation for boundary condiation in fluent, how I can simulate Evaporation for one of Boundary Condiations.

I don't want to use multiphase, I want only to Set Evaporation for Boundary Condiation.

I will be appricated, if someone can help me in this way .

Maria Jesus January 1, 2013 21:59

Quote:

Originally Posted by Dariush53 (Post 399335)
In my work I need to simulate evaporation for boundary condiation.

I am not familiar with fluent completely.

I have one questaion about setting Evaporation for boundary condiation in fluent, how I can simulate Evaporation for one of Boundary Condiations.

I don't want to use multiphase, I want only to Set Evaporation for Boundary Condiation.

I will be appricated, if someone can help me in this way .

Dear Dariush:

I'm going to asume that you are working over the pond and a constant temperature. So, if that's the matter, then you need to put de absolute humidity as Relative Humidity at 100% in that boundary.

I hope thats work OK.

Annananana June 25, 2013 17:01

Frequency in evaporation-condensation model
 
Hi!

Im totaly new in ansys Fluent. I've started with modeling evaporation and condensation. But I absolutely cannot understand evaporation and condensation frequencies. What are they and how should one set them. I''ve red Help about this model, but there's not a word about these frequencies. There is an accommodation coefficient, but it is for condensation and it is not frequency. Maybe they are connected somehow with evaporation/condensation velocities? :confused:
I'd really appreciate it, if you could help me.

Thank you very much.
Anna

Gimlas July 1, 2013 06:39

On the contrary, Users manual clearly states that evaporation and condensation frequencies are purely empirical factors. The problem is that you have to guess these values in order to fit the simulation results to the experimental data.

Annananana July 1, 2013 08:02

Dear Gimlas,

thank you very much. Could You possibly point where it is written in Help more detailed. I read it in 16.7.5 Evaporation-Condensation Model, and there I found only this "By default, the coefficient for both evaporation and condensation is 0.1."

Again thank You very much for the answer.
Anna.

Gimlas July 2, 2013 10:23

Take a look here:

http://www.sharcnet.ca/Software/Flue...ug/node728.htm

Quote:

Enter the Evaporation Frequency and Condensation Frequency model constants. Those values are 0.1 by default. Note that the bubble diameter and accommodation coefficient are usually not very well known, which is why the coefficient can be fine tuned to match experimental data.
I hope that will help you in your research.

Annananana July 3, 2013 17:48

Gimlas,
Thank You very much! You've been very helpful.

All the best,
Annananana.

eliastorca September 25, 2013 11:59

elias
 
I'm also working with mixture model and evaporation-condensation model for mass transfer but finding convergence problems. My case is a long and small diameter tube where the pressure drops due to friction with the walls and the fluid (refrigerant at its liquid state) has to change from liquid to gas. I define both phases and imposse velocity inlet and pressure outlet conditions but I find convergence problems. Could anyone help me? Gimlas, I can't enter in the website you propose

aasrith1296 April 27, 2014 01:37

someone please tell me how to simulate evaporation of water from an open beaker and hence determine the mass lost by evaporation..........


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