Problem 11 [Marks 2.0]

Performance data of a centrifugal water pump is shown in the Table below for water at 20°C

(Lpm = litres per minute).

a) For each row of data, calculate the pump efficiency (%). Show all units and unit

conversions for full marks.

b) Estimate the volumetric flow rate V(Lpm) and the net head (m) at BEP of the pump.

c) Plot the pump's performance data: H (m), bhp (W), n (%) as a function of V.

d) Supposed the pump used in a piping system has a system requirements

Hrequired = (22-21) + bV2, where the elevation difference 22-z₁ = 15 m, and co-efficient

b = 0.025 m/(Lpm)². Estimate the operating point of the system, Voperating (Lpm) and

Hoperating (m).

V.Lpm

0.0

6.0

12.0

18.0

24.0

36.0

H.m

47.5

46.2

42.5

36.2

26.2

15.0

0.0

bhp, W

142

153

164

172

174

174