Learning Forum

[Samuel ZIADI]

Hi,

I’m currently having trouble with the steady simulation of the transonic compressor NASA rotor 67 ( full stage) in fluent. I have run the case in CFX and found a great match with the experimental data. However, when i try to run it with fluent with the same conditions the results are different, and the isentropic efficiency is higher as well as the velocity contours. The pressure ratio remains the same. I don't understand why does anybody have a clue or some advice? I can send you my results if you need. 

My conditions are the following: 

• Turbulence: k-epsilon scalable wall function,
• Inlet: P= 101325 Pa and T= 288.15 K normal to boundary
• Outlet: Ps= 137 000 Pa as an average pressure.
• Interface : mixing plane

I also initialized the axial velocity to get rid of the reverse flow by putting the axial velocity at the inlet: 

X velocity = 164 m/s

Thanks for your help ! 

[RK]

Hello Samuel, 

1. May I know by how what percentage the results vary in Fluent when compared to CFX?
2. Which version of Ansys Fluent are you using? 
3. Is the case fully converged in Fluent? Are the residuals low enough, fluxes balanced and report definitions stabilized? 
4. You could insert a few pictures of the contours and vectors so it would also give us a better idea. 

[Samuel ZIADI]

Hello,

Thanks for your help.I'll answer your questions point by point :

• My adiabatic efficiency varies from 2.25 % when compared to CFX. I'll upload the report below.
• I am using the 2022 R2 version of ANSYS Fluent
• The residuals did converged to my absolute criteria of 10e-5 in 407 interations. My reports ( pressure ratio, temperature ratio, mass flow rate and efficiency) are balanced as well as the mass imbalance.
• Here are my velocity contours, static temperature contours, static pressure contours and relative veloctity vectors at various spans to give you an idea. 

If you need futher information or any other results don't hesitate to ask me. 

Velocity :

 

 

Temperature :

Pressure :

Adiabatic efficiency report :