mass imbalance at the inlet, interface, outlet

CFDturbomachinery · October 30, 2014, 12:16

In my turbine simulation, there is some mass imbalance between the inlet, interface, and outlet. I have two domain: stator and rotor, connected by an interface. When i checked the mass flow through the interface, there was a huge difference (say 60 lps at inlet, 3 lps at the interface, and 58 lps at outlet). why is there very little mass flow through the interface, which should exactly the same 60 lps at all locations?
Thanks much.

JuPa · October 30, 2014, 12:20

I don't have turbo machinery experience so I'll talk in broad terms. The first and obvious question is have you properly defined your setup? Do the tutorials simulate turbo machinery problems the same way you are?

Secondly have your residuals reduced sufficiently?

Lastly, are your inlets and outlets far away from where the action occurs?

CFDturbomachinery · October 30, 2014, 12:54

Thanks RicochetJ,. yes i checked the tutorials and did the setup in the same way as in tutorials...inlets and outlets are far way though..my redisudals reduced to 10-4 but not less than that...

October 30, 2014, 12:16	mass imbalance at the inlet, interface, outlet	#1
CFDturbomachinery New Member Sharon Wilcox Join Date: Aug 2014 Location: California, USA Posts: 21 Rep Power: 12	In my turbine simulation, there is some mass imbalance between the inlet, interface, and outlet. I have two domain: stator and rotor, connected by an interface. When i checked the mass flow through the interface, there was a huge difference (say 60 lps at inlet, 3 lps at the interface, and 58 lps at outlet). why is there very little mass flow through the interface, which should exactly the same 60 lps at all locations? Thanks much.

October 30, 2014, 12:20		#2
JuPa Senior Member Mr CFD Join Date: Jun 2012 Location: Britain Posts: 361 Rep Power: 15	I don't have turbo machinery experience so I'll talk in broad terms. The first and obvious question is have you properly defined your setup? Do the tutorials simulate turbo machinery problems the same way you are? Secondly have your residuals reduced sufficiently? Lastly, are your inlets and outlets far away from where the action occurs? CFDturbomachinery likes this.

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October 30, 2014, 12:54		#3
CFDturbomachinery New Member Sharon Wilcox Join Date: Aug 2014 Location: California, USA Posts: 21 Rep Power: 12	Thanks RicochetJ,. yes i checked the tutorials and did the setup in the same way as in tutorials...inlets and outlets are far way though..my redisudals reduced to 10-4 but not less than that...