Water-Lifting Devices – Pumps - Practices of Irrigation and On-farm Water Management - page 477

(4) Explain the factors affecting the practical suction lift of pump.
(5) What are the features of centrifugal pump? Describe the working principles of
centrifugal pump.
(6) Write short note on the following (in connection to centrifugal pump): (a)
Priming, (b) Cavitation, (c) Specific speed, (d) Affinity laws.
(7) Describe the features, working principle, merits and limitations of the follow-
ing pumps: (a) Turbine pump, (b) Submergible pump, (c) Volute pump, (d)
Air-lift pump, (e) Bucket pump, (f) Jet pump.
(8) Deduce the formula for calculating power requirement of pump.
(9) Briefly describe the pump installation, operation and control principles and
procedures.
(10) What are the hydraulics of water pumping?
(11) Explain the discharge and pressure calculation for pump connection in series
and parallel.
(12) What is pump curve? Briefly explain how you will select a pump for its best
performance.
(13) Six pumps are connected in series, each one pumping 40 GPM at 35 PSI. What
is the total output in flow volume and pressure?
(14) Five pumps are connected in parallel, each one pumping 15 GPM at 22
PSI. What is the total output in flow volume and pressure?
(15) The discharge capacity of a pump is 0.068 m 3 /s. The pump is lifting water
from a depth of 33 m. Calculate the water power.
(16) A centrifugal pump has been installed to a depth of 27 m. The pump is dis-
charging 2.8 cusec (ft 3 /s) water. Determine the capacity of the motor to operate
the pump. Assume motor efficiency of 88%.
(17) A submersible pump lifts 60,000 l of water per h against a total head of 30 m
Determine the power requirement to lift the water in (i) kilowatt, and (ii) horse
power.
(18) In a maize growing area, the cultivable land is 90 ha and wheat will be culti-
vated to all of the lands. The permissible interval between two irrigations at
peak period is 12 days and the depth of irrigation required for that particular
soil and agro-climatic region at peak period is 5.0 cm. If the total head for
pumping is 35 m, pump efficiency is 87%, motor efficiency is 85%, and the
maximum allowable operating period of the pump is 12 h/day, determine:
(i) the pump capacity required for that command area,
(ii) capacity of the motor, and
(iii) electric power required.