A centrifugal pump tested at nominal speed 1750 rpm

Mechanical Engineering May 23, 2021

A centrifugal pump tested at nominal speed 1750 rpm. Data measured during the test are given in the following table:

Rate of flow (L/s)	Suction pressure(mm Hg)	Discharge pressure kgf/cm2	Motor current amp
0	58.61	3.73	18
31.5	37.93	3.39	26.2
50.5	6.9	2.98	31
63	-22.56	2.61	33.9
69.5	-39.11	2.34	35.2
75.7	-58.76	1.99	36.3
88	-100.1	1.14	38
94.6	-124.4	0.6	39

The diameters of the suction and delivery pipes are 15 cm. The motor is supplied at 460 volt, 3 phase and has a power factor of 0.875 and has a constant efficiency of 90%.

A) Calculate by hand the net head delivered and the efficiency of the pump at flow rate of 63 L/s.

B) Use excel sheet and its formula to solve the equations and plot the pump head, power input, and efficiency versus the pump flow rate.