Which of the following pump is successfully used for lifting water to the boilers?
Centrifugal pump
Reciprocating pump
Jet pump
Airlift pump
Correct Answer :
C. Jet pump
Related Questions
A hydraulic intensifier normally consists of
Two cylinders, two rams and a storage device
A cylinder and a ram
Two coaxial rams and two cylinders
A cylinder, a piston, storage tank and control valve
A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit power of the wheel is
0.25 kW
0.75 kW
1.75 kW
3.75 kW
Which of the following pump is generally used to pump highly viscous fluid?
Centrifugal pump
Reciprocating pump
Air lift pump
Screw pump
In reaction turbine, draft tube is used
To transport water downstream without eddies
To convert the kinetic energy to flow energy by a gradual expansion of the flow cross-section
For safety of turbine
To increase flow rate
In a centrifugal pump, the regulating valve is provided on the
Casing
Delivery pipe
Suction pipe
Impeller
Power required (in watts) to drive a centrifugal pump is (where Hm = Manometric head in metres, w = Specific weight in N/m3, Q = Discharge of the pump in m3/s, and ηo = Overall efficiency of the pump)
(w Hm) / (Q × ηo)
(w Hm Q) / ηo
(w Q) / (Hm × ηo)
(w Q ηo) / Hm
The unit speed of the turbine runner is
N/√H
N/H
N/H3/2
N/H²
For 450 m head of water, _________ shall be used.
Pelton wheel
Kaplan turbine
Francis turbine
None of these
Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between
Lift and resultant force
Drag and resultant force
Lift and tangential force
Lift and drag
Air vessels in reciprocating pump are used to
Smoothen flow
Reduce acceleration to minimum
Increase pump efficiency
Save pump from cavitations
The specific speed of a centrifugal pump, delivering 750 litres of water per second against a head of 15 metres at 725 r.p.m., is
24.8 r.p.m.
48.2 r.p.m
82.4 r.p.m.
248 r.p.m
In an outward 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
The hydraulic efficiency of an impulse turbine is the
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
Kinematic similarity is said to exist between the model and the prototype, if both of them
Have identical velocities
Are equal in size and shape
Are identical in shape, but differ only in size
Have identical forces
According to fan laws, for fans having constant wheel diameter, the air or gas capacity varies
Directly as fan speed
Square of fan speed
Cube of fan speed
Square root of fan speed
If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge
Same quantity of liquid
0.75 Q
Q/0.75
1.5 Q
By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is
39.2 %
48.8 %
84.8 %
88.4 %
A ship with jet propulsion draws water through inlet orifices at right angles to the direction of its motion. The propelling force of the jet is (where a = Area of the jet, Vr = Relative velocity of the jet and ship = V + v, v = Velocity of the ship, and V = Velocity of the jet issuing from the ship)
waVr /g × (Vr + v)
waVr /g × (Vr - v)
waVr /g × (Vr + v)²
waVr /g × (Vr - v)²
When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be
Horizontal
Nearly horizontal
Steep
First rise and then fall
In order to avoid cavitation in centrifugal pumps
The suction pressure should be high
The delivery pressure should be high
The suction pressure should be low
The delivery pressure should be low
The maximum hydraulic efficiency of an impulse turbine is (where φ = Angle of blade tip at outlet)
(1 + cos φ)/2
(1 - cos φ)/2
(1 + sin φ)/2
(1 - sin φ)/2
An impulse turbine is used for
Low head of water
High head of water
Medium head of water
High discharge
Braking jet in an impulse turbine is used
To break the jet of water
To bring the runner to rest in a short time
To change the direction of runner
None of these
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
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
Multistage centrifugal pumps are used to obtain
High discharge
High head
Pumping of viscous fluids
High head and high discharge
In a reciprocating pump, air vessels are used to
Smoothen the flow
Reduce suction head
Increase delivery head
Reduce acceleration head
The force exerted by a jet of water impinging normally on a plate which due to the impact of jet, moves in the direction of jet with a velocity v is
[wa (V - v)]/2g
[wa (V - v)]/g
[wa (V - v)²]/2g
[wa (V - v²)]/g
The number of buckets on the periphery of a Pelton wheel is given by
(D/2d) + 5
(D/2d) + 10
(D/2d) + 15
(D/2d) + 20
Hydraulic accumulator is used for
Accumulating oil
Supplying large quantities of oil for very short duration
Generally high pressures to operate hydraulic machines
Supplying energy when main supply fails