UDF to change heat transfer coefficient

eng_yasser_2020 · March 17, 2014, 10:45

Dear, all

I am using FLUET to model a two concentric cylinders (Steady-state & 2-D). The gap between cylinders is filled with gas. I want to add a boundary condition (convection boundary) in the wall between the gas, inner and outer cylinder. I have a convection coefficient as a function of "Rayleigh No. = f(Th-Tc)" not a constant value. My problem is:

- How to write a UDF for the convection coefficient which is a function in gas properties (thermal conductivity, visco, Cp, .....) and it is also a function in temperature difference (Th-Tc)??

- I mean how to write a UDF uses the material properties like (k, Cp, meu,....)???. and uses temperature diff. of two material (Th[solid]-Tc[gas])??

Thanks all

vpFluent · July 1, 2016, 10:47

Hi eng_yasser_2020,

Did you find an answer for this problem?

Thanks

March 17, 2014, 10:45	UDF to change heat transfer coefficient	#1
eng_yasser_2020 New Member Yasser Join Date: Mar 2014 Posts: 7 Rep Power: 13	Dear, all I am using FLUET to model a two concentric cylinders (Steady-state & 2-D). The gap between cylinders is filled with gas. I want to add a boundary condition (convection boundary) in the wall between the gas, inner and outer cylinder. I have a convection coefficient as a function of "Rayleigh No. = f(Th-Tc)" not a constant value. My problem is: - How to write a UDF for the convection coefficient which is a function in gas properties (thermal conductivity, visco, Cp, .....) and it is also a function in temperature difference (Th-Tc)?? - I mean how to write a UDF uses the material properties like (k, Cp, meu,....)???. and uses temperature diff. of two material (Th[solid]-Tc[gas])?? Thanks all

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July 1, 2016, 10:47		#2
vpFluent New Member Víctor Join Date: Jul 2016 Posts: 1 Rep Power: 0	Hi eng_yasser_2020, Did you find an answer for this problem? Thanks