While you may be able to model the flow within a shell-and-tube heat exchanger using Fluent and calculate the heat transfer coefficient (U=q/A⌂T) at various locations over the transfer surface, know that you will only get out what someone else has put in, albeit indirectly through property and transport relationships. That is to say, it may or may not accurately correspond to an actual heat exchanger--even if the flows are all reasonably accurate on a gross scale. This is an "exercise" and not an "experiment". You should compare any results you obtain to measured heat transfer coefficients: inside tubes, through bends and tube sheets, across tube bundles, over and through baffles, etc. There is no substitute for measurements.
Hello, after you have run your simulation, you can go to post-process (results option) and then draw a line on the surface that you want your heat transfer coefficient. Selecting charts will allow you to chose the deriction on the x-axis and then select heat transfer coeffcient for the y-axis. But those parameters must be selected before you run the iterations, under the calculate button (right after initialization) there is an option data file, from which you can select all parameters desired in the post-process. Good luck