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
Correct Answer :
B. Square of fan speed
Related Questions
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
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
The Fourneyron turbine is _________ reaction turbine.
An axial flow
An inward flow
An outward flow
A mixed flow
In a centrifugal pump, the regulating valve is provided on the
Casing
Delivery pipe
Suction pipe
Impeller
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
A Pelton wheel working under a constant head and discharge, has maximum efficiency when the speed ratio is
0.26
0.36
0.46
0.56
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, the horse power required will be
Same
0.75 B.H.P.
B.H.P./0.75
1.5 B.H.P.
Multistage centrifugal pumps are used to obtain
High discharge
High head
Pumping of viscous fluids
High head and high discharge
In a centrifugal pump, the liquid enters the pump
At the top
At the bottom
At the canter
From sides
Specific speed for reaction turbines ranges from
0 to 4.5
10 to 100
80 to 200
250 to 300
The force exerted (in Newton) by a jet of water impinging normally on a fixed plate is (where w = Specific weight of water in N/m3, a = Crosssectional area of jet in m², and V = Velocity of jet in m/s)
waV / 2g
waV / g
waV² / 2g
waV² / g
Multistage centrifugal pumps are used to
Give high discharge
Produce high heads
Pump viscous fluids
All of these
Discharge (Q) of a centrifugal pump is given by (where D = Diameter of impeller at inlet, b = Width of impeller at inlet, and Vf = Velocity of flow at inlet)
Q = π.D.Vf
Q = π.b.Vf
Q = π.D.bf.V
Q = D.b.Vf
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
Motion of a liquid in a volute casing of a centrifugal pump is an example of
Rotational flow
Radial
Forced spiral vortex flow
Spiral vortex flow
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.
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 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
A hydraulic coupling belongs to the category of
Power absorbing machines
Power developing machines
Energy transfer machines
Energy generating machines
A double overhung Pelton wheel has
Two jets
Two runners
Four jets
Four runners
Puck up the wrong statement about centrifugal pump
Discharge a diameter
Head a speed²
Head a diameter
Power a speed⁴
The working of which of the following hydraulic units is based on Pascal's law?
Air lift pump
Jet pump
Hydraulic coupling
Hydraulic press
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
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
Which of the following turbine is preferred for 0 to 25 m head of water?
Pelton wheel
Kaplan turbine
Francis turbine
None of these
High specific speed of turbine implies it is
Propeller turbine
Francis turbine
Impulse turbine
None of the above
Maximum impulse will be developed in hydraulic ram when
Waste valve closes suddenly
Supply pipe is long
Supply pipe is short
Ram chamber is large
Which of the following is not a reaction turbine?
Fourneyron turbine
Journal turbine
Thomson's turbine
Pelton wheel
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
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