Hydraulics – Important Questions – Question No.5

For the system shown in the figure below, it is required to transfer water from tank A ( WL = 75 m ) to tank B ( WL = 95 m ) and tank C ( WL = 65 m ) at a rate of 150 l/sec and 100 l/sec respectively. The pipe diameter is 400 mm for the first 2 km till junction J and 350 mm for the remaining 1.5 km. Friction coefficient f is taken constant for all pipes at 0.015 ( neglect local losses ). A 200 mm automatic rate of flow control valve shall be installed at the inlet pipe to tank C to control the flow at 100 l/sec all the time. Losses in the pipe from J to C can be neglected.

Find the required pumping head.

Calculate the head losses through the valve and the required valve opening % to achieve the required flow of 100 l/sec to tank C.

If the pump is chosen with the characteristic shown in the figure below, draw the system curve and find the actual operating flow rate in all pipes. Find the new adjusted opening percentage for the flow control valve.