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StefanG June 27, 2012 02:49

How to use values of a plane cutting the domain for inlet conditions?
Dear all,

I have the case that I want to simulate a flow channel containing a combustion chamber in which I want to inject vaporized kerosene. The problem is that my computational ressources are quite limited. By now I have results for my flow channel without injecting anything. As I need a very fine mesh in the injection region (which leads to a big mesh), I want to cut my flow channel by a plane upstream the injection point and use these results from this plane as my inlet conditions for my case with injection and then just calculating this part.

By now I have no idea how I could manage this. Any help and suggestions are highly appreciated!

Best regards,

ghorrocks June 27, 2012 07:39

Have a look at the profile boundary condition option.

StefanG June 27, 2012 09:05

Thanks for your hint, Glenn. This is exactly what I was looking for.

But now I have problems Importing it. I performed the following steps:

First I created a plane in ANSYS CFX Post. Then I exported the data on this plane to a BC Profile. Afterwards I started CFX Pre and wanted to Import it, but it crashes everytime.

I exported data for all variables except of that for heat flux.

Any idea what could be the reason?

p.galimutti June 27, 2012 09:22

in the cfd post go to file--> export--> velocity & other variables required at the plane.

you should be able to get a .csv file with physical co-ordinates and their corresponding variable values.

i don't remember importing, but i'll post the rest after i get accesss to CFX.

but if this is what you have done ignore it!

StefanG June 27, 2012 09:26

Dear Peter,

this is exactly what I did, but I want to export values for all variables. So I chose costum export and not total pressure or velocity option for export as with this options it is only possible to export a part of the variables.

But with this custom option CFX Pre crashes when I want to import my file.

When I choose total pressure option instead it works fine, but as I wrote I would like to have tha values for all variables. :)

p.galimutti June 27, 2012 09:39

you just need velocity or pressure and thermal bcs for initialization.

if it crashes it may be due to systems limited resources as you mentioned earlier.

Probably what you can do is give initial condition in 'Initial value specification' in the 'Solver Manager'. All you need to do is use the previous result file. however it may warn you that the initial mesh is not matching the new mesh, but it's alright, the values get interpolated.


StefanG June 28, 2012 03:56

As Inlet I want to use a total pressure bc, but if I just export and import the pressure and velocity values I will loose the turbulence, right?

p.galimutti June 28, 2012 09:29

1 Attachment(s)
then try the last step in my previous post. it will initialize all the data! it's pretty easy...this is the screenshot of how you can use previous results using solver manager

StefanG July 2, 2012 04:08

But the problem is, that in the combustion chamber the flow is completely subsonic, but if I interpolate the results from the whole flow channel, also the supersonic region in the flow channel will be taken into account, right?

StefanG July 3, 2012 08:05

Another question:

I have the problem that my y coordinate in the case from which I want to export the values of the plane differs from these I want to import them as my inlet boundary condition. Is it possible to make a coordinate transformation when I want to import the values?

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