Problem No 1. (30 Points)
A 37-cm-diameter centrifugal pump, running at 2140 rpm with water at 20 deg C, produces the
following performance data:
Q (cubic meter/sec) 0 0.05 0.10 0.15 0.20 0.25 0.30
H (m) 105 104 102 100 95 85 67
P (kw) 100 115 135 171 202 228 249
Efficiency 0
Two identical pumps with above characteristics are to be used at 2140 rpm to pump water at 20
deg C vertically upward through 100 m of commercial steel pipe with roughness height of
0.046 mm.
Should they be in series or in parallel?
What is the proper pipe diameter for most efficient operation? (Use f = 0.02 for initial guess)
100m
$E = 0.046 \text{ mm}$
$H_{sys} = 100 + \frac{(100)}{2 \cdot 9.81} \left( \frac{0.2}{\pi d^2 / 4} \right)^2$
