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July 7, 2014, 23:38 
heat transfer coefficient for the fluid / solid interface

#1 
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sarah
Join Date: Aug 2010
Posts: 41
Rep Power: 9 
Hi,
I am using nonequilibrium model in porous zone in Ansys Fluent 14.5. for specifying heat transfer coefficient for the fluid / solid interface, I have written the following udf #include "udf.h" DEFINE_PROFILE(Heat_trans_coeff,t,i) { cell_t c; real Nu,Re,Pr; real dens, visc; /*Fluid*/ real cond, cp; /* Fluid*/ real d_p; real por;/*Porosity of the bed*/ d_p=0.06; por=0.36 begin_c_loop(c,t) { dens = C_R(c,t); /*Density of fluid*/ visc = C_MU_L(c,t); /*Viscosity fluid*/ cond = C_K_L(c,t); /*Conductivity fluid*/ cp = C_CP(c,t); /*Specific heat fluid*/ Re = ND_MAG(C_U(c,t),C_V(c,t),C_W(c,t))*d_p*dens*por/visc ; /*Reynolds number has been calculated based on pore velocity*/ Pr = cp*visc/cond ; Nu = 2.+ 1.1 * pow(Re,0.6) * pow(Pr,1./3.); F_PROFILE(c,t,i) = Nu*cond/d_p ; } end_c_loop(c,t) } However this code cannot be interpreted in FLUENT. The error message is "c_loop_last: undeclared variable" I would be grateful if somebody help me! 

July 29, 2014, 10:44 

#2 
New Member
Join Date: Nov 2013
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Hello:
Were you able to solve your problem? 

July 31, 2014, 02:50 

#3 
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sarah
Join Date: Aug 2010
Posts: 41
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well, I changed some of the statements to constatnt parameter and the it run!


July 31, 2014, 08:59 

#4 
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Join Date: Nov 2013
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Sarah:
Thanks for your reply. Do you by any chance know how one can get the solid temperature at a specific point in the media by udf? Thank you. 

July 31, 2014, 14:57 

#5 
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sarah
Join Date: Aug 2010
Posts: 41
Rep Power: 9 
you're welcome
while you use non equilibrium model , the software creats solid zone itself so you can observe the variation of Temp on that ! also you can create new plane with specific points to see more details. regards 

August 23, 2014, 18:08 
udf for heattransfercoefficientfluidsolidinterface

#6 
New Member
othman
Join Date: Aug 2014
Posts: 1
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Dear Pr Sarah
I work on the heat transfer in porous media, and I need a UDF for the heat transfer coefficient fluid/solid that is a function of the solid temperarue and the fluid temperature Thank's to answer me Best regards 

April 25, 2016, 20:50 
Udf heat transfer

#7 
New Member
Junia Mendes
Join Date: Apr 2016
Posts: 7
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Good night,
I'm working with heat transfer and I've had serious problems. Can you help me? 

April 26, 2016, 04:59 

#8 
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Bruno Machado
Join Date: May 2014
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April 29, 2016, 08:42 
My code heat transfer

#9 
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Junia Mendes
Join Date: Apr 2016
Posts: 7
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heat_udf_1.h
It's my code. I'm working with tho phases in Eulerian Model. I'm having trouble describing each stage in my UFD. The error is pointed out in this line: heat_kmiec_1980 (c cell_t, Thread * ti, Thread * tj) 

April 29, 2016, 08:48 

#10  
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Junia Mendes
Join Date: Apr 2016
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Quote:
Fallow my udf. Thanks 

May 12, 2016, 04:40 

#11 
New Member
gui
Join Date: Oct 2013
Posts: 10
Rep Power: 6 
Dear members of the forum
I need a UDF for the heat transfer coefficient, considering the properties change with the temperature. My function is very similar to the one Sarah posted here, if anyone knows how to correct that function that would be great! Thank you, G Last edited by guilbemloco; May 12, 2016 at 05:47. 

May 12, 2016, 09:58 

#12 
New Member
gui
Join Date: Oct 2013
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Hello Sarah,
Could you please show me the UDF you created after you changed some parameters to constant? Thank you 

May 17, 2016, 08:44 

#13 
New Member
gui
Join Date: Oct 2013
Posts: 10
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Well, I found that in this code there is a ";" missing after the declaration of "por=0.36".
I added that and I was able to interpret the function normally. 

May 17, 2016, 13:12 

#14 
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Junia Mendes
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May 18, 2016, 02:27 

#15 
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gui
Join Date: Oct 2013
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Sure, it is this:
#include "udf.h" DEFINE_PROFILE(Heat_trans_coeff,t,i) { cell_t c; real Nu,Re,Pr; real dens, visc; /*Fluid*/ real cond, cp; /* Fluid*/ real d_p; real por;/*Porosity of the bed*/ d_p=0.018; por=0.3; begin_c_loop(c,t) { dens = C_R(c,t); /*Density of fluid*/ visc = C_MU_L(c,t); /*Viscosity fluid*/ cond = C_K_L(c,t); /*Conductivity fluid*/ cp = C_CP(c,t); /*Specific heat fluid*/ Re = ND_MAG(C_U(c,t),C_V(c,t),C_W(c,t))*d_p*dens*por/visc ; /*Reynolds number has been calculated based on pore velocity*/ Pr = cp*visc/cond ; Nu = 2.+ 1.1 * pow(Re,0.6) * pow(Pr,1./3.); F_PROFILE(c,t,i) = Nu*cond/d_p ; } end_c_loop(c,t) } I was able to interpret in windows and to compile in linux systems, the reason is not clear thought. 

May 18, 2016, 08:28 

#16  
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Junia Mendes
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Quote:


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