[engrmansoor2534]

Dear Experts
I am doing a heat transfer simulation in ANSYS Fluent. the case is that water is flowing in a uniformly heated tube. its a 3D laminar flow. the problem i am facing is about the application of correct boundary conditions. the inner wall of the tube is at a constant temperature. the outer wall of the tube is adiabatic. the inlet temperature and velocity of water is known. i want to get the mass weighted outlet temperature of water. the main problem is that if I specify a constant surface temperature at the inner wall of the tube, what conditions should i specify for the water outer surface which is in contact with the inner wall of the tube.
kindly help me in this regard
[attachment:1]water-tube-geometry.png[/attachment]