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 %
Correct Answer :
C. 84.8 %
Related Questions
An impulse turbine is used for
Low head of water
High head of water
Medium head of water
High discharge
Indicator diagram of a reciprocating pump is a graph between
Flow vs. swept volume
Pressure in cylinder vs. swept volume
Flow vs. speed
Pressure vs. speed
Dynamic 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
None of the above
The flow ratio of Francis turbine is defined as the ratio of the
Velocity of flow at inlet to the theoretical jet velocity
Theoretical velocity of jet to the velocity of flow at inlet
Velocity of runner at inlet to the velocity of flow at inlet
None of the above
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
Impulse turbine is generally fitted
At the level of tail race
Little above the tail race
Slightly below the tail race
About 2.5 m above the tail race to avoid cavitations.
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
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
Which place in hydraulic turbine is most susceptible for cavitations?
Inlet of draft rube
Blade inlet
Guide blade
Penstock
The force exerted by a jet of water (in a direction normal to flow) impinging on a fixed plate inclined at an angle θ with the jet is
waV/2g × sinθ
waV/g × sinθ
waV²/2g × sin2θ
waV²/g × sinθ
Any change in load is adjusted by adjusting following parameter on turbine
Net head
Absolute velocity
Blade velocity
Flow
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
In a centrifugal pump, the liquid enters the pump
At the top
At the bottom
At the canter
From sides
The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is _______ of the jet velocity,
One-fourth
One-half
Three-fourth
Double
The working of which of the following hydraulic units is based on Pascal's law?
Air lift pump
Jet pump
Hydraulic coupling
Hydraulic press
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
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.
Casting of a centrifugal pump is designed so as to minimize
Friction loss
Cavitations
Static head
Loss of kinetic energy
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
If the ratio's of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have.
Geometric similarity
Kinematic similarity
Dynamic similarity
None of these
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
Head developed by a centrifugal pump depends on
Impeller diameter
Speed
Fluid density
Both (A) and (B) above
A hydraulic coupling belongs to the category of
Power absorbing machines
Power developing machines
Energy transfer machines
Energy generating machines
Geometric 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
For very high discharge at low pressure such as for flood control and irrigation applications, following type of pump is preferred
Centrifugal
Axial flow
Reciprocating
Mixed flow
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
Which of the following hydraulic unit is used for transmitting increased or decreased torque to the driven shaft?
Hydraulic ram
Hydraulic intensifier
Hydraulic torque converter
Hydraulic accumulator
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
Overall efficiency of a centrifugal pump is the ratio of
Energy available at the impeller to the energy supplied to the pump by the prime mover
Actual workdone by the pump to the energy supplied to the pump by the prime mover
Energy supplied to the pump to the energy available at the impeller
Manometric head to the energy supplied by the impeller per kN of water
Mechanical efficiency of a centrifugal pump is the ratio of
Energy available at the impeller to the energy supplied to the pump by the prime mover
Actual workdone by the pump to the energy supplied to the pump by the prime mover
Energy supplied to the pump to the energy available at the impeller
Manometric head to the energy supplied by the impeller per kN of water