[Ice man]

Hi
I have cross flow finned tube heat exchanger with perforated annular fins as shown below.



constant temp. B.C applied to inner diameter of the pipe, I tried to calculate HTC by [q=h*A(Ts ـــ Tref)]. Heat flux (q) value in perforated fin must be larger than solid fin to produce smaller surface temperature than solid fin as we can see in pic.
On the contrary happen in my model just in case of (q). I use this method to find (q), Is it right