[eromon84]

Evening,

I am currently undertaking a project that requires me to model a stage of a steam turbine and model multiphase flow through it. Unfortunately the ratio of nozzles to rotors is not conducive to modeling a nozzle and rotor row in one mesh. 20 nozzles to 151 rotor blades.

I can only have 512000 elements aswell. I can not find out how to run a simulation for my nozzles and save the values ( transient) at the outlet of the nozzle mesh to a file to be read as inlet values in my rotor simulation. Can someone please explain how this is conducted?

I am using Ansys Fluent 14.0

[eromon84]

please can someone respond with some advice on this.

[macfly]

Hi eromon,

There is a way, here's how : http://www.cfd-online.com/Forums/flu...tml#post427287

Now, if you don't know what are scheme files, etc., you will have to google a little bit and see by yourself how it works in Fluent. It's not difficult, but you will have to invest a couple of hours.

Good luck,
Frank

[eromon84]

thank you very much macfly, i at least know what it is I should be searching for on google ^^ . Does this require any C or C++ programming knowledge?

[macfly]

Scheme is a programming language itself: http://rosettacode.org/wiki/Category:Scheme

This webpage is particularly useful when your looking for code bits to execute some task, it shows you how to do it in whatever language: http://rosettacode.org/wiki/Category:Programming_Tasks

And this document can help: http://hpc.hud.ac.uk/w/index.php/Fil..._Reference.pdf

[eromon84]

Hi again,

I have been reading the code in the link you sent me, and also learning more about programming with Scheme. Experimented abit myself with it in Fluent.

While I understand the commands for saving a Temperature profile , I am still not clear on how this profile is read in to a particular boundary within another simulation.

You have a line in your code that is not very clear for me to understand

(if (file-exists? "D:\Model2\T.prof") (ti-menu-load-string "define/boundary-conditions/wall/...ugly line answering many questions...")) ; define profile boundary condition

Is this some UDF that is defining the boundary condition for Model 1 based on output from Model 2? I understand most of the loop that you wrote...just not the part about how to read in a profile to a boundary.

For my case I have a Rotor ( Model 1 ) and exit Stator ( Model 2 ) and need some way of the temperature, pressure etc at exit of Model 1 being read in to the inlet boundary of Model 2 and then Model 2 is initialized based on this inlet boundary profile.

As I said, I can export the profile from Model 1 correctly now it seems, just how to read it in to a particular boundary in my Stator (Model 2) and have that particular profile used to initialize it.

I appreciate all the advise you have given me already, just there is so little documentation out there it seems on this aspect of fluent.

Thank you.

[macfly]

Hi eromon,

The "...ugly line answering many questions..." is a series of answers to questions in order define a boundary condition. It looks like "no no yes 0.5 no"... Define boundary conditions manually in the TUI and you will understand what I mean. When Fluent reads a scheme where a boundary condition is defined in it, the line has to include the answers to those questions. This line is very model specific.

Somewhere in the process of defining a boundary conditions (e.g. a velocity profile), you answer "yes" to a question for defining the BC from a profile, and then you answer the other questions. You have to define the BC manually in the TUI in order to determine what series of answers you have to include in the "ugly line".

Hope I'm clear....!

Frank

[eromon84]

Yeah I understand now. Plus after writing my previous post I carried on playing around with Fluent and understood better now how to load these profiles into a boundary condition.

What i might do is to first find a solution for Model 1 using known data. Then export Temperature profile. Go to Model 2, Load profile, and set this profile at inlet boundary manually.

Then I will execute the scheme files in both systems. From my understanding of how this works the profile data should be overwritten each time I read it in; so long as it has the same name and its referring to the same wall/surface.

My only concern is if I need to keep re-initializing using hybrid initialization after each reading in of a profile. The way I see initialization working is that it discards solution data and starts from zero iterations / time steps again. Is this correct?

I don't want to zero the flow data in the Model 2 Domain, I just need the flow to adjust itself to varying inlet pressures / temperatures over the time period I am running the simulation for.