Multistage centrifugal pumps are used to obtain
High discharge
High head
Pumping of viscous fluids
High head and high discharge
Correct Answer :
B. High head
Related Questions
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
The specific speed of a turbine is given by the equation
N√P / H3/2
N√P / H²
N√P / H5/4
N√P / H3
The optimum value of vane exit angle for a centrifugal pump impeller is
10-15°
20-25°
30-40°
50-60°
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 %
In a centrifugal pump casing, the flow of water leaving the impeller, is
Rectilinear flow
Radial flow
Free vortex motion
Forced vortex
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 %
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 width of the bucket for a Pelton wheel is generally ________ the diameter of jet.
Double
Three times
Four times
Five times
Pressure intensifier increases the pressure in proportion to
Ratio of diameters
Square of ratio of diameters
Inverse ratio of diameters
Square of inverse ratio of diameters
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 Thomson's turbine is __________ reaction turbine.
An axial flow
An inward flow
An outward flow
A mixed flow
The flow 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
According to fan laws, at constant weight of air or gas, the speed, capacity and pressure vary
Directly as the air or gas density
Inversely as square root of density
Inversely as density
As square of density
In a Kaplan turbine runner, the numbers of blades are generally between
2 to 4
4 to 8
8 to 16
16 to 24
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.
High specific speed of turbine implies it is
Propeller turbine
Francis turbine
Impulse turbine
None of the above
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
The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is
40 %
50 %
60 %
80 %
In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by
Designing new impeller
Trimming the impeller size to the required size by machining
Not possible
Some other alterations in the impeller
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
The maximum number of jets, generally, employed in an impulse turbine without jet interference are
Two
Four
Six
Eight
In a centrifugal pump, the regulating valve is provided on the
Casing
Delivery pipe
Suction pipe
Impeller
Any change in load is adjusted by adjusting following parameter on turbine
Net head
Absolute velocity
Blade velocity
Flow
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
Multistage centrifugal pumps are used to
Give high discharge
Produce high heads
Pump viscous fluids
All of these
The unit speed of the turbine runner is
N/√H
N/H
N/H3/2
N/H²
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
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
One horsepower is equal to
102 watts
75 watts
550 watts
735 watts
Delivery head of a centrifugal pump is
Directly proportional to N
Inversely proportional to N
Directly proportional to N²
Inversely proportional to N²