high temperature in a coupling simulation

sheintz · September 22, 2010, 05:21

Hello,
i'm trying to simulate the flow into a bend (90°) with a coupling between Star-CCM+ and GT-Power.
The boudaries are :
inlet, bend and outlet temperature : 300K
inlet pressure : sinusoidal from 1 to 1,5 bar (period 0,04 s)
bend and outlet pressure : 1 bar
compressible ideal gas (O2 and N2)
I can simulation the flow but the temperature in the bend is 1300K at the end.
Why do I get this temperature ?
Thank you in advance
Best regards
Simon

nomad · September 23, 2010, 13:43

Is the flow fully converged? Are the residuals and any flow quantities you are measuring fully converged? Is this 1300K only in a few cells or across a bigger region?

sheintz · September 26, 2010, 05:22

Quote:

Originally Posted by nomad

Is the flow fully converged? Are the residuals and any flow quantities you are measuring fully converged? Is this 1300K only in a few cells or across a bigger region?

Hello,
The high temperature is located in a big region of the bend.
Can I use the residuals when I calculate unsteady ? My residuals are onto 10^6 for Tdr and 10^4 for the others (for a steady calculation it's not good and for a unsteady simulation?).
Thank you
Best regards

nomad · September 30, 2010, 14:56

The size of the residual doesn't really matter so long as the value, or the mean of the residual oscillation remains fairly constant from one iteration to the next.

September 22, 2010, 05:21	high temperature in a coupling simulation	#1
sheintz Member Heintz Simon Join Date: Sep 2009 Location: Germany Posts: 36 Rep Power: 17	Hello, i'm trying to simulate the flow into a bend (90°) with a coupling between Star-CCM+ and GT-Power. The boudaries are : inlet, bend and outlet temperature : 300K inlet pressure : sinusoidal from 1 to 1,5 bar (period 0,04 s) bend and outlet pressure : 1 bar compressible ideal gas (O2 and N2) I can simulation the flow but the temperature in the bend is 1300K at the end. Why do I get this temperature ? Thank you in advance Best regards Simon

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September 23, 2010, 13:43		#2
nomad Member John Join Date: Aug 2009 Posts: 92 Rep Power: 17	Is the flow fully converged? Are the residuals and any flow quantities you are measuring fully converged? Is this 1300K only in a few cells or across a bigger region?

September 30, 2010, 14:56		#4
nomad Member John Join Date: Aug 2009 Posts: 92 Rep Power: 17	The size of the residual doesn't really matter so long as the value, or the mean of the residual oscillation remains fairly constant from one iteration to the next.