Fluid Mechanics and Hydraulic Machinery Mid - II, November - 2014

1.The mechanical efficiency of an impulse turbine is
  • Ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
  • Ratio of the actual work available at the turbine to the energy imparted to the wheel
  • Ratio of the Work done on the wheel to the energy of the jet
  • None of the above
Answer: C
2.Geometric 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
Answer: C
3.The unit discharge through the turbine is
Answer: A
4.Which of the following turbine is preferred for 0 to 25 m head of water?
  • pelton wheel
  • Kaplan turbine
  • Francis turbine
  • None of these
Answer: B
5.The overall efficiency of a reaction turbine is the ratio of
  • Power produced by the turbine to the energy actually supplied by the turbine
  • Actual work available at turbine to the energy imparted to the wheel
  • Work done on the wheel to the energy ( or head of water) actually supplied to the turbine
  • None of these
Answer: A
6.The maximum number of jets, generally, employed in an impulse turbine without jet interference are
  • Two
  • four
  • six
  • eight
Answer: C
7.A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the
  • Kinetic head
  • velocity head
  • manometric head
  • static head
Answer: C
8.The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is
  • 40%
  • 50%
  • 60%
  • 80%
Answer: B
9.The cavitations in a hydraulic machine
  • Caused noise and vibration of various parts
  • Reduces the discharge of a turbine
  • Causes sudden drop in power output and efficiency
  • All of the above
Answer: D
10.Governing of a turbine means
  • The head is kept consant under all conditions of working
  • The speed is kept constant under all conditions of working
  • The discharge is kept constant under all conditions of working
  • all one of the above
Answer: B
11.In an ___________the pressure energy of water is converted into kinetic energy.
Answer: Impulse turbine
12.Specific speed of an impulse turbine ranges from ________
Answer: 12 to70
13.In axial flow turbine water flows _________to the axis of the turbine shaft.
Answer: parallel
14.________turbine is used for low heads and large quantities of flow.
Answer: Kaplan
15.Specific Speed of a turbine Ns is____________
Answer:
16.In a centrifugal pump the sum of suction head and delivery head is known as _______
Answer: Static head
17.In centrifugal pumps cavitation is reduced by ___________
Answer: overall efficiency
18.The flow ratio in case of a centrifugal pump varies from ________
Answer: 0.1 to 0.25
19.Unit power of turbine is given by the expression Pu = __________
Answer: P / H3/2
20.Coefficient of discharge of a reciprocating pump = _____________
Answer: Qact / Qthe