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-   -   NASA Rotor 67 (2D) in CFX (http://www.cfd-online.com/Forums/cfx/78391-nasa-rotor-67-2d-cfx.html)

Saima July 20, 2010 11:22

NASA Rotor 67 (2D) in CFX
 
Hi All,

I am doing NASA rotor 67 profile(2D) in CFX, when i import 2D meshing in CFX it automatically convert in 3D by taking unit width.. I picked section number-6 which is on staking angle 50 deg.

I know all data of that section. Like inlet out static and total pressure and temperatutre with absolute, relative and meridonal velocities. I have rotaional speed of blade.

1. I put inlet: Total temp and Total Pressure
Outlet: static pressure and static temp

2. I put inlet: Mass flow rate
Outlet: static pressure and static temp
3. I put inlet: Total temp and Total Pressure
Outlet: Mass flow rate

In all cases i took airfoil as a rotating with blade speed around 16,000.0 RPM.

But i havent got good result. All the time my inlet and outlet total temperature is same in all three cases. Why is that?

I took shroud and hub as a symmetry condition.

I want to calculate total efficiency which is function of inlet and outlet total pressure and temperature.

Kindly suggest me what shud i do.

Thank you and Regards,

ghorrocks July 20, 2010 23:46

If they all define the same flow you will get the same flow. Total pressure/temperature approximately equals the static pressure/temperature when the velocity is small so it is easy to see why they can be the same. If your defined pressure difference is the same in case 1 as you get in case 2 or 3 then you are just defining the same flow a different method, so will get the same answer.

Saima July 29, 2010 14:50

Quote:

Originally Posted by ghorrocks (Post 268256)
If they all define the same flow you will get the same flow. Total pressure/temperature approximately equals the static pressure/temperature when the velocity is small so it is easy to see why they can be the same. If your defined pressure difference is the same in case 1 as you get in case 2 or 3 then you are just defining the same flow a different method, so will get the same answer.

In real data T01 = 288K
P01 = 101352 Pa

Ps2 = 127523.60 Pa

and T02 = 340
P02 = 164757.0 Pa

but i am getting T02 = 288.17K
P02 = 113526.23 Pa

I choose 1 with total pressure and tem at inlet and static pressure outlet.
I fixed whole domain stationary and select my blade rotating with speed 16046 RPM.If i take domain rotation it doesn't run and gave error right away.

I chose periodic conditions but periodicity translation because if i took rotational it doesn't run and gave error right away.

CFX automatically covert 2D air foil in 3D but with small thicknes. So i took top and bottom as Hub and shroud but with symmetry boundry conditions. I tried Wall but i was not run.

I choose Material :Air ideal Gas.
Heat Transfer Model : Total Energy
Turbulance Model: SST

Kindly suggest me y is that?

Thank you


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