Hydraulic Machines-Fluid Machineries - Set 02 - ObjectiveBooks

Hydraulic Machines-Fluid Machineries - Set 02

Practice Test: Question Set - 02

1. In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by
    (A) Designing new impeller
    (B) Trimming the impeller size to the required size by machining
    (C) Not possible
    (D) Some other alterations in the impeller

2. Which of the following pump is successfully used for lifting water to the turbines?
    (A) Centrifugal pump
    (B) Reciprocating pump
    (C) Jet pump
    (D) Air lift pump

3. 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
    (A) Same
    (B) 0.75 B.H.P.
    (C) B.H.P./0.75
    (D) 1.5 B.H.P.

4. A jet of water is striking at the centre of a curved vane moving with a uniform velocity in the direction of jet. For the maximum efficiency, the vane velocity is ________ of the jet velocity
    (A) One-half
    (B) One-third
    (C) Two-third
    (D) Three-fourth

5. In a centrifugal pump, the liquid enters the pump
    (A) At the top
    (B) At the bottom
    (C) At the canter
    (D) From sides

6. Kinematic similarity is said to exist between the model and the prototype, if both of them
    (A) Have identical velocities
    (B) Are equal in size and shape
    (C) Are identical in shape, but differ only in size
    (D) Have identical forces

7. For very high discharge at low pressure such as for flood control and irrigation applications, following type of pump is preferred
    (A) Centrifugal
    (B) Axial flow
    (C) Reciprocating
    (D) Mixed flow

8. The flow ratio of Francis turbine is defined as the ratio of the
    (A) Velocity of flow at inlet to the theoretical jet velocity
    (B) Theoretical velocity of jet to the velocity of flow at inlet
    (C) Velocity of runner at inlet to the velocity of flow at inlet
    (D) None of the above

9. The maximum number of jets generally employed in impulse turbine without jet interference is
    (A) 4
    (B) 6
    (C) 8
    (D) 12

10. The specific speed (Ns) of a centrifugal pump is given by
    (A) (N√Q)/H2/3
    (B) (N√Q)/H3/4
    (C) (N√Q)/H
    (D) (N√Q)/H5/4

11. Medium specific speed of turbine implies it is
    (A) Propeller turbine
    (B) Francis turbine
    (C) Impulse turbine
    (D) Any one of the above

12. 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?
    (A) Pelton wheel with one nozzle
    (B) Pelton wheel with two or more nozzles
    (C) Kaplan turbine
    (D) Francis turbine

13. Puck up the wrong statement about centrifugal pump
    (A) Discharge a diameter
    (B) Head a speed²
    (C) Head a diameter
    (D) Power a speed⁴

14. The flow ratio in case of Francis turbine varies from
    (A) 0.15 to 0.3
    (B) 0.4 to 0.5
    (C) 0.6 to 0.9
    (D) 1 to 1.5

15. In reaction turbine, draft tube is used
    (A) To transport water downstream without eddies
    (B) To convert the kinetic energy to flow energy by a gradual expansion of the flow cross-section
    (C) For safety of turbine
    (D) To increase flow rate

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