Hydroelectric installation—M . Fig. P3.11 shows a small hydroelectric installation. Water from the large mountain reservoir flows steadily through a steel pipe of 12-in. nominal diameter and effective...

Hydroelectric installation—M . Fig. P3.11 shows a small hydroelectric installation. Water from the large mountain reservoir flows steadily through a steel pipe of 12-in. nominal diameter and effective length 1,500 ft into a turbine. The water is ultimately discharged through a short length of 12-in. pipe to the atmosphere, where the elevation is 600 ft below the surface of the reservoir. If the water flow rate is 12.5 ft3/s, and the turbine/generator produces 425 kW of useful electrical power, estimate the following: (a) The efficiency of the turbine/generator combination. (b) The pressure (psig) at the inlet to the turbine. (c) The power (kW) dissipated by pipe friction. (d) The velocity gradient (s−1) at the pipe wall. Also, what would probably happen if during an emergency a large gate valve at the turbine inlet were suddenly closed during a period of a few seconds? Data: Internal diameter of pipe = 11.939 in. Effective roughness = 0.00015 ft. Viscosity of water = 1.4