[weili]

hey guys,
i'm studying mechanical engineering in germany.
i'm actually working on a centrifugal fan and i have some problem in my project. I have to simulate a mixing model with rotating impeller with a stationary jet (Düse) and a fan housing (Gehäüse) by using ansys cfx 13. It is a steady-state study.

My Question is:
how to make proper set up for the interface between the outlet of the jet and the inlet of the impeller and the interface between outlet of the impeller and the fan hosuing ?

i have already try with mixing model: frozen rotor with the pitch change: none, but i get a warning :
In Analysis 'Flow Analysis 1' - Domain Interface 'R1 to S1': The interface is placed at a rotor-stator interface and the pitch change option of 'None' has been selected. This option should only be used when the overall extent and shape of each side of the interface perfectly match and the surfaces are aligned with each other. It may therefore be suitable when full 360 degree or exactly equal pitch components are being analyzed.

I will be grateful if anyone can help me.

Best gerads,
weili

[Graham81]

Changing the pitch change ratio to Value and then set it '1' will get rid of the error message, but assumes exactly that: a pitch ratio across the rotor stator interface of 1. If the stationary jet and fan housings have no stator blades, this is accurate. Otherwise, I would advise going transient.

[weili]

Thank for the advise.
Actually there is no stator blades at jet and fan hosung.
I hat try what you taught me, but i get a error by cfx solver manager

The ANSYS CFX partitioner exited with return code 1.
Details of error:-
----------------
Error detected by routine MAKDAT
CDANAM = BBMAX CDTYPE = REAL ISIZE = 317280
CRESLT = FULL

can you guide me how to set up the interface between outlet of jet and inlet of impeller and interface between outlet of impeller and fan housing seperately.

actually the interface between outlet of jet and inlet of impeller are two circles which are already coincide
and the interface betwwen outlet of impeller and the fan hosuing are also two surfaces of cylinder which are also coincide.

thank

[ghorrocks]

Have you done the CFX tutorials? Your question seems to be a basic setup issue.

Also - I hate posts titled "urgent". If it is urgent you can get support from the ANSYS support rep and pay for it. On this forum the help is free, but it comes in its own good time. And help also comes quicker if you post sufficient information about your simulation - an image and your CCL file would help.

[weili]

To be honest I do not have so much time to go though the cfx tutorial in details, but i had already scan though it. And i‘m not vey clear with the usage of frozen rotor and the pitch change option. Can anyone explain to me in details every single option.

[Graham81]

Dear weili,

Im sorry but I have to agree with ghorrocks on this one. If you do not have the time to do the minimum yourself, you cant expect others to put in their time to answer your questions. Unless you hire a consultant ofcourse.

Graham

[weili]

hi Graham81,

i 'm a newbie in ansys cfx.
in my case for the interfaces
i used frozen rotor. picth change : none, i get a warning in cfx-pre.
i used frozen rotor. picth change : value and set it '1', i get rid of the warning in cfx-pre, but i get a warning in cfx solver manager that show me that i have to use pitch change : none.

Both of them i cannot load a low speed fan report in cfx-post. There is a error there.

I just want to know which type of the domain interface between stator and rotor should i use and which type of pitch change?

there are no similar case in tutorials that can give me a guide.

[cdegroot]

Originally Posted by weili

To be honest I do not have so much time to go though the cfx tutorial in details, but i had already scan though it. And i‘m not vey clear with the usage of frozen rotor and the pitch change option. Can anyone explain to me in details every single option.

I doubt anyone will take the time to describe all of the details of every single option! That's that the manual is for.

You say you do not have time to go through the tutorials, but I think that is actually the fastest way to solve your problem. You don't have to do them all. Just go through the turbomachinery-related ones. There's only a few of them and I'm sure you can get through them in an hour or two.

[cdegroot]

Also, if you are having problems post an image of what you are doing and a CCL file and I am sure someone will take a look at it.

[weili]

Hi cdegroot


i'm using directly a turbo mode: fan
where can i get my ccl file?

[cdegroot]

To save CCL: File > Export > CCL.

Be sure to save all objects (it's a check box).

[weili]

thank cdegroot.

there is my model image and ccl file

hope someone can help me

[cdegroot]

In the CFX Tutorial "Flow in an Axial Turbine Stage" 14.5.1.2 Component Definitions it says to insert the stationary part first then the rotating part with the warning:

Note:**The components must be ordered as above (stator then rotor) in order for the interface to be created correctly. The order of the two components can be changed by right-clicking on S1 and selecting Move Component Up.

Did you do this? I'm looking at the CCL and they are ordered the opposite, but maybe it's alphabetical. It seems like in the CCL the interfaces are set up properly. Something to check anyways.

Based on the error you receive it seems like maybe a memory issue. How many mesh points do you have and how much memory does your system have?

[weili]

i think the number of mesh points is not very much, because this is only my first sample.
and my com memory is 12 GB. i think this is sufficient to run it.

[cdegroot]

Sounds like memory is fine then. It's strange that it crashes in the partitioner. Does the partitioner work for a non-turbo application?

[weili]

i try before only with the rotating impeller, it works fine

[cdegroot]

That rules out a configuration issue then. If you can upload the .cfx file or .def file I can take a closer look.

[weili]

how do i get .cfx file or .def file ?

[cdegroot]

The .cfx file is the one you save in CFX-pre and the .def is the solver input file. Both should be in your working directory.

[weili]

both are too big to be upload