## Fluids

#### Natural Circulation

• ramesbas
Subscriber

Hi all, I am new to Fluent (very new). I am planning to do simple simulation for my master thesis. Idea is to find out how much of the steam is evaporated. scheme is From drum Water flow through downcomer in Downward direction (Water with Geodetic height which is driving force) then it enters the vertical Heating surface (converts water into water steam mixture by heating) and the back to drum where generated steam leaves the system. My queries are 1. Water + steam mixture can be evlautaed 2. Any kind of tutorial is available? Thanks for helping out guys

• raul.raghav
Subscriber

The evaporation-condensation model in Fluent can be used for your case.

Fluent: Evaporation-Condensation Model

The following youtube videos show the modeling of evaporation in Ansys Fluent. The video has a horizontal heating surface and you can see how the water vapor is modeled to leave the system.

Attached is a pdf file which describes all the phase change models in Fluent, if you want to explore more options available.

• ramesbas
Subscriber

Dear Raul, I have seen the You tube video . It gives some idea but your presentation pdf has some more valuable inputs which is more interesting. Is it possible to sent me an Geometry and meshing to Baskar.Ramesh@b-tu.de ? It would be helpfull for start learning!

• raul.raghav
Subscriber

Ramesh, you might not find a lot of tutorials on evaporation modeling. So you can create a geometry real quick based on the youtube video I shared. It should be fairly easy to make the geometry shown. Once you're familiar with Fluent and this model, in particular, you can design your geometry and build your mesh.  Since you're "very new" as you mention, feel free to ask questions along the way.

• ramesbas
Subscriber

Hi Raul, By chance do u have geometry of no of tubes or pipes connection to a Manifold or is ther any tutorials on it . I am not finding any in you tube. Your pointers will be helpfull!

• raul.raghav
Subscriber

Can you verify if you're looking for something like this: CFD Analysis on exhaust Manifold for a 4 cylinder engine

You have to be a little more specific about which tutorial you are looking for.

• ramesbas
Subscriber

• Raef.Kobeissi
Subscriber

As it looks like a complex geometry, I would recommend you to simplify it by just designing the part you want to analyze. You also need to remember that this is going to be a transient simulation requiring a small time step, hence, it would take a long time to be resolved at an acceptable time.

• ramesbas
Subscriber

Dear Raef, I am not sure How well i understood your comments since i am Raw new to Ansys Fleunt. However , I have started preparing the Geometry. The point i would like to see is Pipe 'G' whether it recirculates the water back from Top manifold or what should be the adequate size for the Water recirculation!Let me post the once i finish the Geometry. Mean time if you think i need to know any tutorial for this two phase flow please let me know. Appreciate if you could enhance me on this terms 'going to be a transient simulation requiring a small time step, hence, it would take a long time to be resolved at an acceptable time'

• ramesbas
Subscriber

Dear Raef & Raul,

Just a quick help. I have just drawn a five tubes with a top and bottom manifold. Here i just need your basic help. I just want to develop from 5 tubes to 150 tubes . Is there a option to copy and expand it ? if possible please provide me the step procedure for the starters. And my basic doubt when i try to work on X-y plane as typical tutorials from you you tube i am not able to select x-y plane and make the changes. Appreciate your help please!!!