Maintaining average temperature at Inlet in cyclic Boundary condition

Luttappy · May 8, 2018, 04:18

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, 07:01

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.

Find the average temperature (Tavg) at INLET after every time step after solving energy equation.
Divide the temperature field of whole computational domain by Tavg (T=T/Tavg)
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

SamuelPei · June 1, 2018, 16:14

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, 03:04

Quote:

Originally Posted by SamuelPei

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

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.

Find the average temperature (Tavg) at INLET after every time step after solving energy equation.
Divide the temperature field of whole computational domain by Tavg (T=T/Tavg)
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

rr3245 · September 11, 2018, 16:44

Quote:

Originally Posted by Luttappy

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, 05:27

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

May 8, 2018, 04:18	Maintaining average temperature at Inlet in cyclic Boundary condition	#1
Luttappy Member HK Join Date: Oct 2015 Location: Madras Posts: 31 Rep Power: 11	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 Last edited by Luttappy; May 16, 2018 at 07:05.

May 16, 2018, 07:01	Maintaining average temperature at Inlet in cyclic Boundary condition	#2
Luttappy Member HK Join Date: Oct 2015 Location: Madras Posts: 31 Rep Power: 11	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. Find the average temperature (Tavg) at INLET after every time step after solving energy equation. Divide the temperature field of whole computational domain by Tavg (T=T/Tavg) 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

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June 1, 2018, 16:14		#3
SamuelPei New Member Samson Join Date: Apr 2016 Posts: 4 Rep Power: 10	Hello Luttappy, did you find out how to set the value for the temperatur with a cyclic inlet boundary condition? Greetings

September 25, 2018, 05:27		#6
pete20r2 Senior Member Peter Baskovich Join Date: Jul 2014 Posts: 127 Rep Power: 12	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