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.
Correct Answer :
D. A Francis turbine is an impulse turbine.
Related Questions
The maximum number of jets generally employed in impulse turbine without jet interference is
4
6
8
12
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
Francis, Kaplan and propeller turbines fall under the category of
Impulse turbines
Reaction turbines
Axial flow turbines
Mixed flow turbines
One horsepower is equal to
102 watts
75 watts
550 watts
735 watts
The overall efficiency for a Pelton wheel lies between
0.50 to 0.65
0.65 to 0.75
0.75 to 0.85
0.85 to 0.90
When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be
Horizontal
Nearly horizontal
Steep
First rise and then fall
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
The optimum value of vane exit angle for a centrifugal pump impeller is
10-15°
20-25°
30-40°
50-60°
Axial flow pump is started with its delivery valve
Kept fully closed
Kept fully open
Irrespective of any position
Kept 50% open
In a Kaplan turbine runner, the numbers of blades are generally between
2 to 4
4 to 8
8 to 16
16 to 24
Slip of a reciprocating pump is negative, when
Suction pipe is short and pump is running at low speeds
Delivery pipe is long and pump is running at high speeds
Suction pipe is short and delivery pipe is long and the pump is running at low speeds
Suction pipe is long and delivery pipe is short and the pump is running at high speeds
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 Fourneyron turbine is _________ reaction turbine.
An axial flow
An inward flow
An outward flow
A mixed flow
The discharge through a reaction turbine with increase in unit speed
Increases
Decreases
Remain unaffected
First increases and then decreases
Which of the following is not an impulse turbine?
Girad turbine
Turgo turbine
Pelton wheel
Kaplan turbine
Casting of a centrifugal pump is designed so as to minimize
Friction loss
Cavitations
Static head
Loss of kinetic energy
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)
A Pelton wheel is
Tangential flow impulse turbine
Inward flow impulse turbine
Outward flow impulse turbine
Inward flow reaction turbine
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
Which of the following turbine is preferred for 0 to 25 m head of water?
Pelton wheel
Kaplan turbine
Francis turbine
None of these
Discharge of a centrifugal pump is (where N = Speed of the pump impeller)
Directly proportional to N
Inversely proportional to N
Directly proportional to N²
Inversely proportional to N²
Delivery head of a centrifugal pump is
Directly proportional to N
Inversely proportional to N
Directly proportional to N²
Inversely proportional to N²
Discharge of a centrifugal pump is
Directly proportional to diameter of its impeller
Inversely proportional to diameter of its impeller
Directly proportional to (diameter)² of its impeller
Inversely proportional to (diameter)² of its impeller
The unit speed of the turbine runner is
N/√H
N/H
N/H3/2
N/H²
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
Multistage centrifugal pumps are used to obtain
High discharge
High head
Pumping of viscous fluids
High head and high discharge
A turbine develops 10000 kW under a head of 25 metres at 135 r.p.m. Its specific speed is
175.4 r.p.m.
215.5 r.p.m.
241.5 r.p.m.
275.4 r.p.m
Centrifugal pump is started with its delivery valve
Kept fully closed
Kept fully open
Irrespective of any position
Kept 50% open
Power required to drive a centrifugal pump is directly proportional to ________ of its impeller.
Diameter
Square of diameter
Cube of diameter
Fourth power of diameter
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