[diwakar]

Hey guys, i'm trying to do a one-way fsi of turbine blade where i'll be importing temperature load from cfx to static thermal and then use that temperature in structural analysis where i have a fixed support n rotational velocity as boundary conditions. Can anybody plz help me with this???

[singer1812]

How are you doing this?

MFX within ANSYS/CFX or in Workbench?

I have only done this using MFX and MAPDL, and if you are not an expert in APDL I dont think I will describe the details on this forum.

If you want to do it within Workbench, cant you just connect the features with drag and drop (at least thats what ANSYS marketing tells me...)

Seriously, there are a few tutorials on this in the help documentation. Read those and respecify your question with a little more focus.

[diwakar]

Hello singer1812, thnx for replying to my post.
I'm not an expert in ANSYS, but i'm trying to do it. i have tried to do it in workbench and i was able to transfer temperature results from CFX to static-thermal but when i transfer this thermal load to structural analysis and also apply rotational velocity to the model, the rotational velocity doesn't seem to contribute to any more stress on the model. i dont know if i can import temperature from CFX and also apply some loads like rotational velocity at same time on the body. So can u plz tell me if its possible to that? if yes then what mistake i have done in my analysis?

[singer1812]

Good, your follow on is a little more detailed.

I dont think your problem lies in the transfer in information. Correct me if I am wrong, but you are getting a successful steady state thermal case with boundary conditions applied from CFX.

Also, it sounds like you are getting a successful structural case with thermal field applied from thermal steady state? (If i am incorrect on this please specify). Also, if you didnt do so, run the structrual, with tmeperature, without rotation added to get a baseline case to compare to (but I am assuming this is the case you are comparing to when you state that rotation isnt adding any more stress on your model).

So from the outside, it looks like an issue on how you set up your structrual case. I suggest running stand alone structural with rotation and no temperature import and make sure that is behaving as you think.

[stumpy]

First, you'd be better off importing a Convection Coefficient to the Steady Thermal analysis instead of a Temperature. Both approaches will give the same solution IF the blade temperature predicted in the Steady Thermal analysis is equal to the thermal boundary condition you applied in CFX. However, that won't generally be true. The Convection Coefficient will be more accurate when the predicted blade temperature is different than the CFX thermal boundary condition.
Second, I assume you have not solved the solid temperature field in CFX (CHT)? If you have, then you should be going straight to the Static Structural analysis.
As Ed suggested, solve your Static Structural analysis with/without the rotational velocity and with/without the imported temperature from the Steady Thermal analysis. There should be no problems combining these.

[diwakar]

hello singer1812,
I tried what u suggested me i.e. analysis with/without rotation & temperature...i have attached some images of the equivalent stress result i got after these analyses...

in all analyses the base of the blade is fixed.
For analysis with only rotational velocity i can see proper stress distribution as u can see in first image.
with_only_rotational_velocity.jpg

For analysis with imported temperature from CFX and rotational velocity suppressed i.e. no rotational velocity...as i have fixed the base, the stress results seem alright like its a displacement caused by fixed base & thermal load...as u can see in second image.
with_temp_without_rotational_velocity.jpg

For analysis with imported temperature & rotational velocity both applied...i think it should show some combined stress distribution on blade...but it just shows stress result similar to 2nd case i.e. stress results like only imported temperature applied...see image below

with_temp_and_rotational_velocity.jpg

I don't know whats wrong in this...can u plz check?

[singer1812]

Diwakar:

Embed your pics. I will not go to an outside link.

But from what you describe, it really seems like an error in setting within your setup in the Mechanical Ansys portion for the sturc/thermal. You will have to trouble shoot that and provide more details just on that part of the model. A good help resourse for ANSYS FEA is xansys.org.

I would suggest one other thing prior to troubleshooting further. For your temperature and rotational structural case, instead of importing your temperature, fix your temp DOF (might want to test two things: first case fixed constant temp for entire model and second case fix half the model at one temp and another at another temp). This might narrow things down a bit more.

[diwakar]

hey singer1812,

i tried the case what u suggested me i.e. no imported temperature from cfx. What i did is, i applied a thermal condition in a normal structural analysis where i also have a rotational velocity & fixed support. i just observed cfx analysis temperature which is around 1250 deg. C and applied that much temperature as thermal load in this structural analysis. But surprisingly the stress distribution is similar(not exact number but similar) to the case with imported temperature & rotational velocity applied...

this following image shows previous case i.e. imported temperature & rotational velocity case-->
with_temp_and_rotational_velocity.jpg


& this pic shows new case with thermal load & rotational velocity(no imported loads at all) -->
no_imported_temperature.jpg

i dont know if stress is supposed to be distributed like that when there's rotational velocity & temperature applied...can u plz check it for me

[singer1812]

Cant comment on goodness of your solution and what is wrong with your solution.

If there is an error, it would appear it would be in your structural setup, and not with the tie-in to the other physics.

Do you have a few hand calcs that you can compare the rotational only and temperature only results to? Perhaps your solution is in the right range?