The ratio of quantity of liquid discharged per second from the pump to the quantity of liquid passing per second through the impeller is known as
Manometric efficiency
Mechanical efficiency
Overall efficiency
Volumetric efficiency
Correct Answer :
D. Volumetric efficiency
Related Questions
The undershot water wheels are those in which
The wheel runs entirely by the weight of water
The wheel runs entirely by the impulse of water
The wheel runs partly by the weight of water and partly by the impulse of water
None of the above
The impeller of a centrifugal pump may have
Volute casing
Volute casing with guide blades
Vortex casing
Any one of these
Head developed by a centrifugal pump is
Proportional to diameter of impeller
Proportional to speed of impeller
Proportional to diameter and speed of impeller
None of the above
The type of centrifugal pump preferred for a specific speed of 20 r.p.m. is
Slow speed pump with radial flow at outlet
Medium speed pump with radial flow at outlet
High speed pump with radial flow at outlet
High speed pump with axial flow at outlet
The ratio of actual work available at the turbine to the energy imparted to the wheel is known as ________ efficiency.
Hydraulic
Mechanical
Overall
None of these
A turbine develops 10000 kW under a head of 25 metres at 135 r.p.m. Its specific speed is
175.4 r.p.m.
215.5 r.p.m.
241.5 r.p.m.
275.4 r.p.m
The unit power developed by a turbine is (where P = Power developed by the turbine under a head of water (H).
P/ √H
P/ H
P/ H3/2
P/ H²
The specific speed from 160 to 500 r.p.m. of a centrifugal pump indicates that the pump is
Slow speed with radial flow at outlet
Medium speed with radial flow at outlet
High speed with radial flow at outlet
High speed with axial flow at outlet
Saving of work done and power by fitting an air vessel to double acting reciprocating pump is of the order of
39.2 %
49.2 %
68.8 %
84.8 %
The overall efficiency of a reaction turbine is the ratio of
Power produced by the turbine to the energy actually supplied by the turbine
Actual work available at the turbine to the energy imparted to the wheel
Workdone on the wheel to the energy (or head of water) actually supplied to the turbine
None of the above
The discharge through a reaction turbine with increase in unit speed
Increases
Decreases
Remain unaffected
First increases and then decreases
In axial flow fans and turbines, fluid enters and leaves as follows
Radially, axially
Axially, radially
Axially, axially
Radially, radially
The hydraulic efficiency of a reaction turbine, is the ratio of
Power produced by the turbine to the energy actually supplied by the turbine
Actual work available at the turbine to energy imparted to the wheel
Workdone on the wheel to the energy (or head of water) actually supplied to the turbine
None of the above
Reaction turbines are used for
Low head
High head
High head and low discharge
Low head and high discharge
The jet ratio is defined as the ratio of the
Diameter of jet to the diameter of Pelton wheel
Velocity of jet to the velocity of Pelton wheel
Diameter of Pelton wheel to the diameter of jet
Velocity of Pelton wheel to the velocity of jet
Puck up the wrong statement about centrifugal pump
Discharge a diameter
Head a speed²
Head a diameter
Power a speed⁴
For centrifugal pump impeller, the maximum value of the vane exit angle is
10° to 15°
15° to 20°
20° to 25°
25° to 30°
According to fan laws, for the fans having constant wheel diameters, the power demand varies
Directly as fan speed
Square of fan speed
Cube of fan speed
Square root of fan speed
Head developed by a centrifugal pump depends on
Impeller diameter
Speed
Fluid density
Both (A) and (B) above
In a centrifugal pump, the regulating valve is provided on the
Casing
Delivery pipe
Suction pipe
Impeller
In an inward flow reaction turbine
The water flows parallel to the axis of the wheel
The water enters at the centre of the wheel and then flows towards the outer periphery of the wheel
The water enters the wheel at the outer periphery and then flows towards the centre of the wheel
The flow of water is partly radial and partly axial
An impulse turbine is used for
Low head of water
High head of water
Medium head of water
High discharge
Which of the following statement is correct as regard to water wheels?
They have slow speeds
They are suitable even for low water heads
They give constant efficiency, even if the discharge is not constant
All of the above
Specific speed for reaction turbines ranges from
0 to 4.5
10 to 100
80 to 200
250 to 300
Medium specific speed of a pump implies it is
Centrifugal pump
Mixed flow pump
Axial flow pump
Any one of the above
Motion of a liquid in a volute casing of a centrifugal pump is an example of
Rotational flow
Radial
Forced spiral vortex flow
Spiral vortex flow
Power required to drive a centrifugal pump is directly proportional to ________ of its impeller.
Diameter
Square of diameter
Cube of diameter
Fourth power of diameter
In centrifugal pumps, maximum efficiency is obtained when the blades are
Straight
Bent forward
Bent backward
Radial
The cavitation in reaction turbines is avoided, to a great extent by
Installing the turbine below the tail race level
Using stainless steel runner of the turbine
Providing highly polished blades to the runner
All of the above
Which of the following statement is correct?
In an impulse turbine, the water impinges on the buckets with pressure energy.
In a reaction turbine, the water glides over the moving vanes with kinetic energy.
In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.
In a reaction turbine, the pressure of the flowing water increases after gliding over the vanes.