5.1-4 (5-1 in text) Fluid flows through a tube with inner diameter D. You have been asked to help interpret some measured data for flow through the tube. Specifically, the heat transfer coefficient, h, has been measured as a function of the tube diameter. Figure P5.1- 4 illustrates the heat transfer coefficient measured in the thermally fully developed region of the tube as a function of the tube diameter; note that the mass flow rate of fluid (m), the type of fluid, and all other aspects of the experiment are not changed for these measurements. (W/m-K) 103 Fully developed heat transfer coef. 10% 105 10 101 0 1 23 4 5 6 Diameter (cm) 7 89 10 Figure P5.1-4: Heat transfer coefficient as a function of diameter (for a constant fluid mass flow rate and fluid type and all other aspects of the problem held constant.) a.) Explain in a few sentences the abrupt change in the heat transfer coefficient observed that occurs at approximately D = 5.5 cm. b.) Explain in a few sentences why the heat transfer is inversely proportional to diameter for diameters above about D = 5.5 cm; that is, why is it true that hoc D for D > 5.5 cm? c.) Sketch your expectation for how Figure P5.1-4 would change if the roughness of the tube wall is increased dramatically.