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Simulation of surge and stall for Rotor 37

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Old   March 28, 2013, 23:32
Post Simulation of surge and stall for Rotor 37
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Maixiaoya
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Hi, dear friends~~
I'm doing a simulation of surge and stall for rotor 37 using the CFX , but I don't know how to set the boundary conditions,can anyone so kind to give me some advice?

Thanks in advance!
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Old   April 1, 2013, 18:45
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Have you read the best practices guide for turbomachinery? It is part of the CFX documentation.
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Old   April 17, 2013, 21:57
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Originally Posted by ghorrocks View Post
Have you read the best practices guide for turbomachinery? It is part of the CFX documentation.
Yeah,I have read the Turbogrid Documentation on the Rotor37, but I think difficult part is to set the boundary conditions for Rotor37, and for the stage 37. I have tried to set set the Inlet flow rate and outlet static pressure, but the ANSYS CFX-pre always stopped abruptly, saying returning error code1.
Can you give me some advice?
Thank you very much.
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Old   April 18, 2013, 06:16
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Surge and stall are effects with complicated separated flow and you would expect difficult convergence with them. Have a look at the FAQs for hints on getting convergence. Also you are almost certainly not going to get a steady state simulation to converge. It will require a transient approach.
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Old   February 16, 2016, 14:06
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Quote:
Originally Posted by ghorrocks View Post
Surge and stall are effects with complicated separated flow and you would expect difficult convergence with them. Have a look at the FAQs for hints on getting convergence. Also you are almost certainly not going to get a steady state simulation to converge. It will require a transient approach.
I can not solve Rotor 37 correctly
508967965.png
508967953.png
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Old   February 16, 2016, 17:10
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Quote:
Originally Posted by Cedric View Post
Yeah,I have read the Turbogrid Documentation on the Rotor37, but I think difficult part is to set the boundary conditions for Rotor37, and for the stage 37. I have tried to set set the Inlet flow rate and outlet static pressure, but the ANSYS CFX-pre always stopped abruptly, saying returning error code1.
Can you give me some advice?
Thank you very much.
Irrespective of surge/stall, your inlet BC is wrong. Use (Po,To,flow angle) at inlet and Ps at exit. Using inlet flow rate is only for an incompressible flow CFD.
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Old   February 16, 2016, 17:12
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Originally Posted by metaliat93 View Post
I can not solve Rotor 37 correctly
Attachment 45223
Attachment 45224
Your CFD looks wrong. CFX will predict quite close to test map, especially axial-flow compressors. Find out what went wrong.
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Old   February 17, 2016, 06:45
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Quote:
Originally Posted by turbo View Post
Your CFD looks wrong. CFX will predict quite close to test map, especially axial-flow compressors. Find out what went wrong.
I check all BC, I don't know where wrong
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Old   February 17, 2016, 22:13
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Originally Posted by metaliat93 View Post
I check all BC, I don't know where wrong
If your mesh, BC and solver settings are OK, then look into all the geometry including tip clearance.
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Old   February 18, 2016, 03:18
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Quote:
Originally Posted by turbo View Post
If your mesh, BC and solver settings are OK, then look into all the geometry including tip clearance.
My domaines: stator+rotor+stator
509101611.jpg

BC on inlet
509101933.jpg

BC on outlet
509102010.jpg
Pout = 105000 [Pa] then was veriable in serial solvering

Settings
509102108.png
509102118.png
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Old   February 18, 2016, 14:54
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It looks you do not have rotor tip clearance, and then you are losing more trust in the prediction.
What interface models were you using on the two interfaces? You don't have to go with two stationary domains.
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Old   February 19, 2016, 03:07
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Quote:
Originally Posted by turbo View Post
It looks you do not have rotor tip clearance, and then you are losing more trust in the prediction.
What interface models were you using on the two interfaces? You don't have to go with two stationary domains.
509187770.jpg this is settings on interface.
Why I don't must use two stationary domaine. I think that need to have domaine to remove influence outlet condition.
Shrout tip only give loss of parametrs.
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Old   February 20, 2016, 10:16
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I assume you used the same stage interface upstream of rotor. No tip clearance simulation should predict even higher pressure ratio and efficiency than test. But yours did not. Where and how did you get the pressure ratio and efficiency on the curve? Only a single R1 is enough to simulate the rotor only case.
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Old   February 22, 2016, 04:42
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Originally Posted by turbo View Post
I assume you used the same stage interface upstream of rotor. No tip clearance simulation should predict even higher pressure ratio and efficiency than test. But yours did not. Where and how did you get the pressure ratio and efficiency on the curve? Only a single R1 is enough to simulate the rotor only case.
I think that simulation without tip clearance must to get results higher that in exper, but you can see it lower. Of course I will solving with tip in a future, but Can not understant why get this results.
I use shot rotor domaine because want to get high results of effenciency, a long rotating gas channel raise length movements of gas, so it is raise gidravlic loss.
I get Pr Rt and EFF on boundary of rotor and stator domaines
509452944.jpg
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Old   February 22, 2016, 13:51
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You should get mass-averaged PR and total absolute temperature at the same location where the test data were obtained. Even in R1 only domain you can set a non-rotating hub area as you want. Again you need to repeat the no-tip-clearance simulation until you get higher performance than test. Clearly your prediction will not be seen in any other CFDs.
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Old   February 24, 2016, 16:29
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Quote:
Originally Posted by turbo View Post
You should get mass-averaged PR and total absolute temperature at the same location where the test data were obtained. Even in R1 only domain you can set a non-rotating hub area as you want. Again you need to repeat the no-tip-clearance simulation until you get higher performance than test. Clearly your prediction will not be seen in any other CFDs.
Ok, understant you. Build without inlet and outlet stationar domaine, only rotating.
509667533.png
509667549.png
thats me setting on the inlet

509667692.png
setting of domaine

Solved with shroud tip (turn on doble precision)
509666165.png
RMS

509666153.png
eff politropic and isoentropic (lower that in exp)
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Old   February 24, 2016, 16:31
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Quote:
Originally Posted by turbo View Post
You should get mass-averaged PR and total absolute temperature at the same location where the test data were obtained. Even in R1 only domain you can set a non-rotating hub area as you want.
509666181.png
massflow at the outlet
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Old   February 25, 2016, 12:49
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Inlet and outlet domains in Turbogrid will let you specify a non-rotating hub in CFX. Every residual needs to be less than 1.0e-5. You need to identify what was the hot tip clearance in the test and what position test map was measured at.
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Old   May 27, 2016, 01:58
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Quote:
Originally Posted by turbo View Post
Inlet and outlet domains in Turbogrid will let you specify a non-rotating hub in CFX. Every residual needs to be less than 1.0e-5. You need to identify what was the hot tip clearance in the test and what position test map was measured at.
again, I do all what you wrote before but, have not got a good results. Can you send in info about meridional position Rotor wheel Rotor 37?
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