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.Management Sciences
Category: Hydraulic Machines
Casting of a centrifugal pump is designed so as to minimize________________?
A. friction loss
B. cavitation
C. static head
D. loss of kinetic energy
E. starting time
Which place in hydraulic turbine is most susceptible for cavitation __________________?
A. inlet of draft rube
B. blade inlet
C. guide blade
D. penstock
E. draft tube exit
Specific speed for reaction turbines ranges from___________________?
A. 0 to 4.5
B. 10 to 100
C. 80 to 200
D. 250 to 300
E. none of the above
Impulse turbine is generally fitted______________________?
A. at the level of tail race
B. little above the tail race
C. slightly below the tail race
D. about 2.5 m above the tail race to avoid cavitation
E. about 2.5 m below the tail race to avoid cavitation
Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of__________________?
A. 39.2%
B. 49.2%
C. 68.8%
D. 84.8%
E. 91.6%.
Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between_________________?
A. lift and resultant force
B. drag and resultant force
C. lift and tangential force
D. lift and drag
E. resultant force and tangential force
A hydraulic accumulator normally consists of________________?
A. two cylinders, two rams and a storage device
B. a cylinder and a ram
C. two co-axial rams and two cylinders
D. a cylinder, a piston, storage tank and control valve
E. special type of pump with storage device and a pressure regulator
When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be__________________?
A. horizontal
B. nearly horizontal
C. steep
D. first rise and then fall
E. none of the above
In centrifugal pumps, maximum efficiency is obtained when the blades are_________________?
A. straight
B. bent forward
C. bent backward
D. radial
E. given aerofoil section
In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by_______________?
A. designing new impeller
B. trimming the impeller size to the required size by machining
C. not possible
D. some other alterations in the impeller
E. none of the above
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