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
Correct Answer :
A. Directly as fan speed
Related Questions
If the net positive suction head (NPSH) requirement for the pump is not satisfied, then
No flow will take place
Cavitation will be formed
Efficiency will be low
Excessive power will be consumed
Puck up the wrong statement about centrifugal pump
Discharge a diameter
Head a speed²
Head a diameter
Power a speed⁴
Reaction turbines are used for
Low head
High head
High head and low discharge
Low head and high discharge
In a reaction turbine, the draft tube is used
To run the turbine full
To prevent air to enter the turbine
To increase the head of water by an amount equal to the height of the runner outlet above the tail race
To transport water to downstream
The efficiency of a hydraulic press is given by (where W = Weight lifted by ram, P = Force applied on plunger, A = Area of ram, and a = Area of plunger)
(W/p) × (A/a)
(p/W) × (a/A)
(W/p) × (a/A)
(p/W) × (A/a)
Medium specific speed of a pump implies it is
Centrifugal pump
Mixed flow pump
Axial flow pump
Any one 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
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
Axial flow pump is started with its delivery valve
Kept fully closed
Kept fully open
Irrespective of any position
Kept 50% open
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
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
Delivery head of a centrifugal pump is
Directly proportional to N
Inversely proportional to N
Directly proportional to N²
Inversely proportional to N²
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
In a Francis turbine runner, the numbers of blades are generally between
2 to 4
4 to 8
8 to 16
16 to 24
Medium specific speed of turbine implies it is
Propeller turbine
Francis turbine
Impulse turbine
Any one of the above
The optimum value of vane exit angle for a centrifugal pump impeller is
10-15°
20-25°
30-40°
50-60°
Head developed by a centrifugal pump depends on
Impeller diameter
Speed
Fluid density
Both (A) and (B) above
The speed of a turbine runner is
Directly proportional to H1/2
Inversely proportional to H1/2
Directly proportional to H3/2
Inversely proportional to H3/2
The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which
Delivers unit discharge under unit head
Delivers unit discharge under unit speed
Develops unit power under unit head
Develops unit power under unit speed
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
Francis turbine is best suited for
Medium head application from 24 to 180 m
Low head installation up to 30 m
High head installation above 180 m
All types of heads
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
Which of the following pump is preferred for flood control and irrigation applications?
Centrifugal pump
Axial flow pump
Mixed flow pump
Reciprocating pump
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 %
Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of
39.2 %
49.2 %
68.8 %
84.8 %
Specific speed for reaction turbines ranges from
0 to 4.5
10 to 100
80 to 200
250 to 300
An impulse turbine is used for
Low head of water
High head of water
Medium head of water
High discharge
For 450 m head of water, _________ shall be used.
Pelton wheel
Kaplan turbine
Francis turbine
None of these
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
A double overhung Pelton wheel has
Two jets
Two runners
Four jets
Four runners