thermal boundary option

club68512 · February 27, 2010, 05:12

hello everyone~
I have a problem about ...heat transfer coefficients that is from
model setup/boundaries/mesh boundaries/mesh block/wall/thermal information/thermal boundary options

there are heat transfer coefficient to fluid 1 &to fluid 2 ,does anybody know that means?
thanks

MuxaB · February 28, 2010, 19:52

if the mesh boundary is of type 'wall' with a specified temperature, then it needs an htc between the wall and adjacent fluid to compute the heat flux at the boundary. The user can defined a different htc for fluid 1 and 2 in two-fluid problems.

does it make sense?

ck5285 · February 28, 2010, 23:55

Michael
i thought the heat transfer coefficient is calculated by the solver while solving the conjugate heat transfer problem? pls help to clarify.

MuxaB · March 1, 2010, 11:23

Yes, the solver will do it if you leave these input entries blank.

club68512 · March 3, 2010, 10:07

Quote:

Originally Posted by MuxaB

if the mesh boundary is of type 'wall' with a specified temperature, then it needs an htc between the wall and adjacent fluid to compute the heat flux at the boundary. The user can defined a different htc for fluid 1 and 2 in two-fluid problems.

does it make sense?

but if I set the 'wall' as copper that have thermal conductivity value(k),does it needs a htc ?

MuxaB · March 3, 2010, 18:27

It does not really matter what material it is made of. The user can either define a constant htc at the fluid/wall interface, or the code will compute it automatically as a function of the materials properties and the flow. In the latter case, it assumes that the contact between copper and fluid is perfect, i.e., no thermal resistance.

February 27, 2010, 05:12	thermal boundary option	#1
club68512 New Member liang liam Join Date: Nov 2009 Location: Taiwan Posts: 28 Rep Power: 16	hello everyone~ I have a problem about ...heat transfer coefficients that is from model setup/boundaries/mesh boundaries/mesh block/wall/thermal information/thermal boundary options there are heat transfer coefficient to fluid 1 &to fluid 2 ,does anybody know that means? thanks

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February 28, 2010, 19:52		#2
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 336 Rep Power: 18	if the mesh boundary is of type 'wall' with a specified temperature, then it needs an htc between the wall and adjacent fluid to compute the heat flux at the boundary. The user can defined a different htc for fluid 1 and 2 in two-fluid problems. does it make sense?

February 28, 2010, 23:55		#3
ck5285 Senior Member Join Date: Mar 2009 Posts: 129 Rep Power: 17	Michael i thought the heat transfer coefficient is calculated by the solver while solving the conjugate heat transfer problem? pls help to clarify.

March 1, 2010, 11:23		#4
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 336 Rep Power: 18	Yes, the solver will do it if you leave these input entries blank.

March 3, 2010, 18:27		#6
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 336 Rep Power: 18	It does not really matter what material it is made of. The user can either define a constant htc at the fluid/wall interface, or the code will compute it automatically as a function of the materials properties and the flow. In the latter case, it assumes that the contact between copper and fluid is perfect, i.e., no thermal resistance.