Consider the heating of an incompressible fluid with velocity Um inside a thin - walled tube. The diameter of the tube is D. Heating is in the hydrodynamically and thermally developed region and the flow is laminar. Incompressible fluid enters the tube at temperature T1 and pressure P1. The tube length of the tube is L. Heating can be done either by condensing steam on the outer surface of the tube, thus maintaining a uniform surface heat flux. Calculate the irreversibility for both of these heating conditions by assuming fluid properties are constants. Discuss.