NLH model

LUO DAN · June 8, 2020, 23:39

hi,
I have a question whether NLH model can be used to simulate centrifugal compressor impeller (no static diffuser, i.e. no rotor stator interaction) and real gas (CO2)? The time-domain unsteady simulation can simulate centrifugal compressor impeller.
thank you

Hamidzoka · June 9, 2020, 07:28

As long as unsteady flow features comes form the relative rotation of adjacent rows NLH can be used. Since it assumes that unsteadiness of flow variables has a zero-averaged value which means that an unsteady behavior is repeated over the time.
In case of a single row unsteadiness has not necessarily a zero-averaged behavior in macro scales. So I think it is not applicable to use NLH in this case.

Regards

LUO DAN · June 10, 2020, 09:21

thank you for your response,
I am also confused about whether the NLH method is suitable for co2 compressor in NUMECA(for condensable gas).
when i use NLH model to conduct unsteady calculation, the case always blew up due to 'thermodynamic tables directory:c:/users/dell\……‘not found.
however, the steady calculation is ok.
thank you!

Hamidzoka · June 11, 2020, 11:27

Hi;
There may be some limitations in application of NLH method.
Have a look a Fine/Turbo users guide.

regards

June 8, 2020, 23:39	NLH model	#1
LUO DAN New Member luo dan Join Date: Sep 2018 Posts: 27 Rep Power: 7	hi, I have a question whether NLH model can be used to simulate centrifugal compressor impeller (no static diffuser, i.e. no rotor stator interaction) and real gas (CO2)? The time-domain unsteady simulation can simulate centrifugal compressor impeller. thank you

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June 9, 2020, 07:28		#2
Hamidzoka Senior Member Hamid Zoka Join Date: Nov 2009 Posts: 282 Rep Power: 18	As long as unsteady flow features comes form the relative rotation of adjacent rows NLH can be used. Since it assumes that unsteadiness of flow variables has a zero-averaged value which means that an unsteady behavior is repeated over the time. In case of a single row unsteadiness has not necessarily a zero-averaged behavior in macro scales. So I think it is not applicable to use NLH in this case. Regards

June 10, 2020, 09:21		#3
LUO DAN New Member luo dan Join Date: Sep 2018 Posts: 27 Rep Power: 7	thank you for your response, I am also confused about whether the NLH method is suitable for co2 compressor in NUMECA(for condensable gas). when i use NLH model to conduct unsteady calculation, the case always blew up due to 'thermodynamic tables directory:c:/users/dell\……‘not found. however, the steady calculation is ok. thank you!

June 11, 2020, 11:27		#4
Hamidzoka Senior Member Hamid Zoka Join Date: Nov 2009 Posts: 282 Rep Power: 18	Hi; There may be some limitations in application of NLH method. Have a look a Fine/Turbo users guide. regards