heat transfer coefficient as initial value

tH3f0rC3 · May 22, 2011, 08:41

Hi there,

I want to model the heat transfer between a hot fluid and a cold solid. Because the whole case has a lot of elements the calculation needs a lot of time.
So I thought about the following:

I will identify the heat transfer coefficient from an easy simulation which is solved very fast with the same properties.
Than I want to set the heat transfer coefficient as an initial value for the following calculation. Because in the following calculation only the solid has to be solved and no fluid is needed.

So my question is: Is it possible to set the heat transfer coefficient as an initial value / boundary condition in one of the heat transfer solvers?

Best Regards,
tH3f0rC3

yipiyaya8 · September 16, 2011, 08:52

I hv also face the same problem...

My case is cooling hot plate with coolent air ...I have to input heat transfer coeff as initial value.
I dont know how to write it!

Kindly help
Thanks

tH3f0rC3 · September 16, 2011, 10:16

My research has shown that it is not easily possible to set up the heat transfer coefficients with OpenFoam.
But it is easy to do this with Fluent.

If you or someone else know how to implement the heat transfer coefficients as boundary conditions to OpenFoam please let me know.

Best Regards,
tH3f0rC3

yipiyaya8 · September 16, 2011, 10:21

Hm...

Perhaps i need to use initial T and mass flow rate as substitution of HTC...

Anyway i will try input HTC for now...I will tell u if i got it!

Regards

tH3f0rC3 · September 16, 2011, 19:25

Ok, thanks.
I look forward to your answer.

Best Regards

yipiyaya8 · September 19, 2011, 06:57

I am now looking for this post ,
http://www.cfd-online.com/Forums/ope...r-restart.html

Also
http://openfoamwiki.net/index.php/Contrib_groovyBC

Playing with the
groovyBC_2Way_coupling_001.tgz

Hope find solution soon...

Regards

eelcovv · September 20, 2011, 04:11

groovyBC is the way to go to impose heat transfer coefficients as a boundary condition for your temperature field. Just calculate in groovyBC the heatflux as qflux=hcof*(T-Tamb); where Tamb is a variable with you ambient temperature, hcof is a variable of the heat flux, and subsequently calculate the temperature gradient according to the post you are referering to (heat flux not constant). Bear in mind that the alphaEff should excist in your solver (i.e. is a field containing the effective heat diffusivity given by alphaEff=alpha+alphat, with alpha=lambda/rho Cp (molecular diffusivity), and alphat=nut/Prt with Prt=0.7 (turbulent prandtl number) for the turbulent diffusivity.
Good luck!
Regards
Eelco

yipiyaya8 · September 21, 2011, 20:58

Quote:

Originally Posted by eelcovv

groovyBC is the way to go to impose heat transfer coefficients as a boundary condition for your temperature field. Just calculate in groovyBC the heatflux as qflux=hcof*(T-Tamb); where Tamb is a variable with you ambient temperature, hcof is a variable of the heat flux, and subsequently calculate the temperature gradient according to the post you are referering to (heat flux not constant). Bear in mind that the alphaEff should excist in your solver (i.e. is a field containing the effective heat diffusivity given by alphaEff=alpha+alphat, with alpha=lambda/rho Cp (molecular diffusivity), and alphat=nut/Prt with Prt=0.7 (turbulent prandtl number) for the turbulent diffusivity.
Good luck!
Regards
Eelco

Hi eelcovv,

I will take ur advise carefully. Really Thanks a lot...Will get back to you if any problem....

Regards

dewey · November 29, 2016, 10:43

Hi i am trying to use groovyBC to use a heat transfer coefficient,

groovyBC is already in code of OF4? or i have to install?

i want to use with a buoyantBoussinesqSimpleFoam, but i dont know how it is the way to use it, i define de Bc in T file?

aero.rajat · June 20, 2018, 02:45

I am facing the exact same problem. i.e. inserting a HTC value in the ./0/T file so that the hot plate undergoes forced convection when placed in the ambient air.
has anyone successfully implemented groovyBC? Dire need of help.

May 22, 2011, 08:41	heat transfer coefficient as initial value	#1
tH3f0rC3 Senior Member Join Date: Mar 2011 Posts: 158 Rep Power: 15	Hi there, I want to model the heat transfer between a hot fluid and a cold solid. Because the whole case has a lot of elements the calculation needs a lot of time. So I thought about the following: I will identify the heat transfer coefficient from an easy simulation which is solved very fast with the same properties. Than I want to set the heat transfer coefficient as an initial value for the following calculation. Because in the following calculation only the solid has to be solved and no fluid is needed. So my question is: Is it possible to set the heat transfer coefficient as an initial value / boundary condition in one of the heat transfer solvers? Best Regards, tH3f0rC3

September 20, 2011, 04:11		#7
eelcovv Senior Member Eelco van Vliet Join Date: Mar 2009 Location: The Netherlands Posts: 124 Rep Power: 19	groovyBC is the way to go to impose heat transfer coefficients as a boundary condition for your temperature field. Just calculate in groovyBC the heatflux as qflux=hcof*(T-Tamb); where Tamb is a variable with you ambient temperature, hcof is a variable of the heat flux, and subsequently calculate the temperature gradient according to the post you are referering to (heat flux not constant). Bear in mind that the alphaEff should excist in your solver (i.e. is a field containing the effective heat diffusivity given by alphaEff=alpha+alphat, with alpha=lambda/rho Cp (molecular diffusivity), and alphat=nut/Prt with Prt=0.7 (turbulent prandtl number) for the turbulent diffusivity. Good luck! Regards Eelco mirko, fumiya, yipiyaya8 and 1 others like this.

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September 16, 2011, 08:52		#2
yipiyaya8 New Member Join Date: Sep 2011 Posts: 10 Rep Power: 14	I hv also face the same problem... My case is cooling hot plate with coolent air ...I have to input heat transfer coeff as initial value. I dont know how to write it! Kindly help Thanks

September 16, 2011, 10:16		#3
tH3f0rC3 Senior Member Join Date: Mar 2011 Posts: 158 Rep Power: 15	My research has shown that it is not easily possible to set up the heat transfer coefficients with OpenFoam. But it is easy to do this with Fluent. If you or someone else know how to implement the heat transfer coefficients as boundary conditions to OpenFoam please let me know. Best Regards, tH3f0rC3

September 16, 2011, 10:21		#4
yipiyaya8 New Member Join Date: Sep 2011 Posts: 10 Rep Power: 14	Hm... Perhaps i need to use initial T and mass flow rate as substitution of HTC... Anyway i will try input HTC for now...I will tell u if i got it! Regards

September 16, 2011, 19:25		#5
tH3f0rC3 Senior Member Join Date: Mar 2011 Posts: 158 Rep Power: 15	Ok, thanks. I look forward to your answer. Best Regards

September 19, 2011, 06:57		#6
yipiyaya8 New Member Join Date: Sep 2011 Posts: 10 Rep Power: 14	I am now looking for this post , http://www.cfd-online.com/Forums/ope...r-restart.html Also http://openfoamwiki.net/index.php/Contrib_groovyBC Playing with the groovyBC_2Way_coupling_001.tgz Hope find solution soon... Regards

November 29, 2016, 10:43		#9
dewey Senior Member alberto Join Date: Apr 2016 Location: Mexico Posts: 117 Rep Power: 10	Hi i am trying to use groovyBC to use a heat transfer coefficient, groovyBC is already in code of OF4? or i have to install? i want to use with a buoyantBoussinesqSimpleFoam, but i dont know how it is the way to use it, i define de Bc in T file?

June 20, 2018, 02:45		#10
aero.rajat New Member rajat tripathi Join Date: May 2018 Location: india Posts: 9 Rep Power: 7	I am facing the exact same problem. i.e. inserting a HTC value in the ./0/T file so that the hot plate undergoes forced convection when placed in the ambient air. has anyone successfully implemented groovyBC? Dire need of help.