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-   -   Maintaining average temperature at Inlet in cyclic Boundary condition (https://www.cfd-online.com/Forums/openfoam-solving/201674-maintaining-average-temperature-inlet-cyclic-boundary-condition.html)

Luttappy May 8, 2018 03:18

Maintaining average temperature at Inlet in cyclic Boundary condition
 
Dear all,
I want to maintain the average temperature at the inlet to fixed value of 1 in my cyclic boundary condition. (streamwise periodic heat transfer)
I have seen the fvOption utility patchMeanVelocityForce to fix the average velocity at any patch to desired value.
Is there any utility available in OpenFOAM to fix the average temperature of any patch?

Thanks in advance:)

Luttappy May 16, 2018 06:01

Maintaining average temperature at Inlet in cyclic Boundary condition
 
Since i am not dealing with actual temperature and my temperature range is from 0 to 1, this can be implemented in OpenFOAM very easily by following way.
  1. Find the average temperature (Tavg) at INLET after every time step after solving energy equation.
  2. Divide the temperature field of whole computational domain by Tavg (T=T/Tavg)
  3. Proceed to next time step:)

In some cases people suggest this procedure after every N time step rather than every time step. This N can be found by trial and error.

If we don't fix average temperature at INLET to a constant value, temperature value inside the domain can go to very very low value (Cold walls + hot fluid entering case) or very very high value (Hot walls + cold fluid entering case). This is because of the cyclic boundary condition applied at INLET and OUTLET.

Please correct me if i am wrong:o

SamuelPei June 1, 2018 15:14

Hello Luttappy,


did you find out how to set the value for the temperatur with a cyclic inlet boundary condition?


Greetings

Luttappy June 21, 2018 02:04

Quote:

Originally Posted by SamuelPei (Post 694324)
Hello Luttappy,


did you find out how to set the value for the temperatur with a cyclic inlet boundary condition?


Greetings

I resolved it in this way.

Quote:

Originally Posted by Luttappy (Post 692509)
Since i am not dealing with actual temperature and my temperature range is from 0 to 1, this can be implemented in OpenFOAM very easily by following way.
  1. Find the average temperature (Tavg) at INLET after every time step after solving energy equation.
  2. Divide the temperature field of whole computational domain by Tavg (T=T/Tavg)
  3. Proceed to next time step:)

In some cases people suggest this procedure after every N time step rather than every time step. This N can be found by trial and error.

If we don't fix average temperature at INLET to a constant value, temperature value inside the domain can go to very very low value (Cold walls + hot fluid entering case) or very very high value (Hot walls + cold fluid entering case). This is because of the cyclic boundary condition applied at INLET and OUTLET.

Please correct me if i am wrong:o


rr3245 September 11, 2018 15:44

Quote:

Originally Posted by Luttappy (Post 696704)
I resolved it in this way.

Hi Luttappy, could you please share your code for this? Maybe your .C files would help. Thanks.

pete20r2 September 25, 2018 04:27

Me too please!
I have a non-uniform cross section periodic channel that this may work for.
Sharing your solution would be very helpful...

Regards
Peter


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