In Fig. 4(a), a flow rate of 60 pi L/min of oil of relative density 0.92 exists in pipeline AB. A small pipe CD is Filled with mercury. The viscosity of the oil mu. oil is the same as that of water and the viscosity of mercury mu Hg is 8 time that of water. The diameter of large pipe AB is 25mm and the small pipe CD is 10mm. Note: 1 L = 10-3 m, muwater= 103 kg/(s middot m), water = 103 kg/m3. (3%) Calculate the Reynolds number based on pipe diameter in large pipe AB. Is it laminar flow? Why? Hint: Recritical 2100. (14%) If the large pipe has a roughness of 0.01cm, what is the pressure gradient between point A and B? What is the direction of the pressure gradient? Hint: refer to Fig. 4(b). (8%)Using result from above, calculate H in the small pipe. If the flow starts and the situation in figure is reached in 1 second without any oscillation of interface in small pipe CD. Calculate the Reynolds number of mercury based pipe diameter in small pipe CD. Is it laminar flow? Fig4(a)
Explanation / Answer
=-gz This equation describes the pressure in a manometer.