Multistage centrifugal pumps are used to
Give high discharge
Produce high heads
Pump viscous fluids
All of these
Correct Answer :
B. Produce high heads
Related Questions
By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. The saving in case of a double acting reciprocating pump is
39.2 %
48.8 %
84.8 %
88.4 %
The speed ratio in case of Francis turbine varies from
0.15 to 0.3
0.4 to 0.5
0.6 to 0.9
1 to 1.5
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
According to fan laws, for fans having constant wheel diameter, the pressure varies
Directly as fan speed
Square of fan speed
Cube of fan speed
Square root of fan speed
The discharge of a double acting reciprocating pump is (where L = Length of stroke, A = Cross-sectional area of piston, and N = Speed of crank in r.p.m.)
L.A.N
2 L.A.N
(L.A.N)/60
(2 L.A.N)/60
Which of the following statement is wrong?
The reaction turbines are used for low head and high discharge.
The angle of taper on draft tube is less than 8°.
An impulse turbine is generally fitted slightly above the tail race.
A Francis turbine is an impulse turbine.
An impulse turbine is used for
Low head of water
High head of water
Medium head of water
High discharge
Which place in hydraulic turbine is most susceptible for cavitations?
Inlet of draft rube
Blade inlet
Guide blade
Penstock
Specific speed for reaction turbines ranges from
0 to 4.5
10 to 100
80 to 200
250 to 300
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
In a reciprocating pump, air vessels are used to
Smoothen the flow
Reduce suction head
Increase delivery head
Reduce acceleration head
The discharge through a reaction turbine ________ with the increase in unit speed.
Decreases
Increases
Remain same
None of these
Multistage centrifugal pumps are used to
Give high discharge
Produce high heads
Pump viscous fluids
All of these
The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship is given by
[2(Vr - v) v]/ Vr²
2(Vr + v) v]/ Vr²
[(Vr - v) v]/ Vr
[(Vr + v) v]/ Vr
The mechanical efficiency of an impulse turbine is
Ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
Ratio of the actual work available at the turbine to the energy imparted to the wheel
Ratio of the Work done on the wheel to the energy of the jet
None of the above
Which of the following statement is correct?
The centrifugal pump is suitable for large discharge and smaller heads.
The centrifugal pump requires less floor area and simple foundation as compared to reciprocating pump.
The efficiency of centrifugal pump is less as compared to reciprocating pump.
All of the above
The specific speed (Ns) of a centrifugal pump is given by
(N√Q)/H2/3
(N√Q)/H3/4
(N√Q)/H
(N√Q)/H5/4
The maximum number of jets generally employed in impulse turbine without jet interference is
4
6
8
12
In a centrifugal pump casing, the flow of water leaving the
Radial
Axial
Centrifugal
Vortex
A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?
Pelton wheel with one nozzle
Pelton wheel with two or more nozzles
Kaplan turbine
Francis turbine
The optimum value of vane exit angle for a centrifugal pump impeller is
10-15°
20-25°
30-40°
50-60°
A Francis turbine is used when the available head of water is
0 to 25 m
25 m to 250 m
Above 250 m
None of these
In a centrifugal pump casing, the flow of water leaving the impeller, is
Rectilinear flow
Radial flow
Free vortex motion
Forced vortex
The Fourneyron turbine is _________ reaction turbine.
An axial flow
An inward flow
An outward flow
A mixed flow
The gross or total head of the turbine is the ________ of the water levels at the head race and tail race.
Sum
Difference
Product
None of these
The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as
Normal speed
Unit speed
Specific speed
None of these
Slip of a reciprocating pump is defined as the
Ratio of actual discharge to the theoretical discharge
Sum of actual discharge and the theoretical discharge
Difference of theoretical discharge and the actual discharge
Product of theoretical discharge and the actual discharge
Low specific speed of a pump implies it is
Centrifugal pump
Mixed flow pump
Axial flow pump
None of the above
Which of the following is not an impulse turbine?
Girad turbine
Turgo turbine
Pelton wheel
Kaplan turbine
Which of the following pump is successfully used for lifting water from deep wells?
Centrifugal pump
Reciprocating pump
Jet pump
Air lift pump