The angle of taper on draft tube is
Greater than 15°
Greater than 8°
Greater than 5°
Less than 8°
Correct Answer :
D. Less than 8°
Related Questions
For starting an axial flow pump, its delivery valve should be
Closed
Open
Depends on starting condition and flow desired
Could be either open or closed
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
Runaway speed of a hydraulic turbine is
Full load speed
The speed at which turbine runner will be damaged
The speed if the turbine runner is allowed to revolve freely without load and with the wicket gates wide open
The speed corresponding to maximum overload permissible
A hydraulic coupling belongs to the category of
Power absorbing machines
Power developing machines
Energy transfer machines
Energy generating machines
The function of guide vanes in a reaction turbine is to
Allow the water to enter the runner without shock
Allow the water to flow over them, without forming eddies
Allow the required quantity of water to enter the turbine
All of the above
The unit speed of the turbine runner is
N/√H
N/H
N/H3/2
N/H²
A hydraulic ram is a device used to
Store the energy of water
Increase the pressure of water
To lift water from deep wells
To lift small quantity of water to a greater height when a large quantity of water is available at a smaller height
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
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 speed of the wheel is
10 r.p.m.
20 r.p.m.
40 r.p.m.
80 r.p.m.
The working of which of the following hydraulic units is based on Pascal's law?
Air lift pump
Jet pump
Hydraulic coupling
Hydraulic press
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
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
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
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
According to fan laws, at constant speed and capacity, the pressure and power vary
Directly as the air or gas density
Inversely as square root of density
Inversely as density
As square of density
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 gross or total head of the turbine is the ________ of the water levels at the head race and tail race.
Sum
Difference
Product
None of these
Air vessels in reciprocating pump are used to
Smoothen flow
Reduce acceleration to minimum
Increase pump efficiency
Save pump from cavitations
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
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
In a centrifugal pump, the regulating valve is provided on the
Casing
Delivery pipe
Suction pipe
Impeller
For small discharge at high pressure, following pump is preferred
Centrifugal
Axial flow
Mixed flow
Reciprocating
Which place in hydraulic turbine is most susceptible for cavitations?
Inlet of draft rube
Blade inlet
Guide blade
Penstock
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
For centrifugal pump impeller, the maximum value of the vane exit angle is
10° to 15°
15° to 20°
20° to 25°
25° to 30°
Any change in load is adjusted by adjusting following parameter on turbine
Net head
Absolute velocity
Blade velocity
Flow
Low specific speed of turbine implies it is
Propeller turbine
Francis turbine
Impulse turbine
Any one of the above
Head developed by a centrifugal pump depends on
Impeller diameter
Speed
Fluid density
Both (A) and (B) above
The maximum number of jets, generally, employed in an impulse turbine without jet interference are
Two
Four
Six
Eight
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 discharge of wheel is
0.25 m3/s
0.5 m3/s
1.5 m3/s
2.5 m3/s