[Ashraf Mimi]

Dear all....
Please i have an important question.... currently i am working on improving the effectiveness of tube-in-tube heat exchanger numerically using FLUENT 6.3.The boundary condition of the fluid in inner tube is Turbulent and for outer tube (Annulus) is Laminar? what is the suitable model of the program can handle and give satisfactory results for this case to validate with experimental work....
My respect....

Dr. Ashraf Mimi

[sache]

U can use K-e Realizable model....
it will give satisfactory result

[Ashraf Mimi]

Thank you and my especially respect for your answer Sache and reply ....
K.e model Realizable as you said is suitable for case above... do you have a reference for your answer???
Which wall near treatment of of the following suitable too?
-Standard wall functions.
-Non-equilibrium wall functions.
-Enhanced wall treatment.
-User-defined wall functions.
I have another question....
Some one of my supervisors told me you should select your limitation of flow for two pipes corresponding to laminar flow Re<2300 or two pipes Turbulent flow Re>4000
What about your opinion for the idea above to overcome the difference in the type of fluid in two tubes if we are not have reference for your answer above???...

Thanks .....

[Ashraf Mimi]

Dear all ....
Please i need answer for my Questions above???

Thanks