4.15 Figure P4.15 shows a pump and pipe network being used to transport heptane at 90°F to a large, elevated storage tank that is closed, but vented to ensure that the pressure above the heptane is atmospheric. The volumetric flow rate of the heptane is 500 gpm.

a. Determine the pressure drop (psi) that the pump must overcome to move the heptane through the discharge pipe.

b. Investigate the effect of the absolute roughness of the pipe. Construct a plot that shows the variation in pressure drop as a function of the absolute roughness for values ranging from 0 to 0.01 ft.