A pipe 10 cm in diameter and 1000 m long is used to pump oil of visco...
Discharge, Q = 1200 litre⁄min
Viscosity, μ = 8.5 poise = 8.5 × 0.1 = 0.85 N s⁄m
Flow velocity = discharge / area
= 275.78
Since the Reynolds number is less than 2000, the flow is laminar. For laminar flow, the friction coefficient is given by
Head loss due to friction in 1000 m length of pipe
The pressure to be developed by the pump can be worked out by applying Bernoulli’s equation between the pump outlet (suffix 1) and the end of the pipeline (suffix 2)
With horizontal line through the pump center,
y1 = 0
and y2 = 300 sin 10° + 700 sin 15° = 233.25 m p2 = 0 as the pressure at the pipe exit is atmospheric Also V1 = V2
∴p1 / w = 233.25 + 768
= 1001.25 m of oil
Power required to develop this pressure
= w Q H
= (0.92 × 1000 × 9.81) × 0.02 × 1001.25
= 180729 Nm⁄s ≈ 180.73 kW
Power of driving motor