Mechanical Engineering - Hydraulic Machines

Exercise :: Hydraulic Machines - Section 4

1. 

The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which

A. delivers unit discharge under unit head
B. delivers unit discharge under unit speed
C. develops unit power under unit head
D. develops unit power under unit speed

Answer: Option C

Explanation:

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2. 

The runaway speed of a hydraulic turbine is the speed

A. at full load
B. at which there will be no damage to the runner
C. corresponding to maximum overload permissible
D. at which the turbine will run freely without load

Answer: Option D

Explanation:

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3. 

The cavitation in a hydraulic machine

A. causes noise and vibration of various parts
B. reduces the discharge of a turbine
C. causes sudden drop in power output and efficiency
D. all of the above

Answer: Option D

Explanation:

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4. 

The type of centrifugal pump preferred for a specific speed of 20 r.p.m. is

A. slow speed pump with radial flow at outlet
B. medium speed pump with radial flow at outlet
C. high speed pump with radial flow at outlet
D. high speed pump with axial flow at outlet

Answer: Option A

Explanation:

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5. 

If the net positive suction head (NPSH) requirement for the pump is not satisfied, then

A. no flow will take place
B. cavitation will be formed
C. efficiency will be low
D. excessive power will be consumed

Answer: Option B

Explanation:

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