Quiznetik

Thermal Engineering 2 | Set 1

1. Nozzle is used to control direction or characteristics of flow.

Correct : A. true

2. In fountains the type of nozzle used is

Correct : D. laminar jet

3. If mach number is less than one then its flow is

Correct : A. subsonic flow

4. The steam leaves the nozzle at a

Correct : A. low pressure and a high velocity

5. When mach number is greater than one the flow is

Correct : B. supersonic

6. In rocket engines the amount of expansion in Nozzle determines the

Correct : C. exit temperature & pressure

7. De-Laval turbine is a

Correct : C. single rotor impulse turbine

8. The Parsons’ reaction turbine has

Correct : D. identical fixed and moving blades

9. What is the critical pressure ratio for initially wet steam?

Correct : A. 0.582

10. The ratio of the useful heat drop to the isentropic heat drop is called

Correct : B. nozzle efficiency

11. Rateau turbine is

Correct : D. pressure compounded turbine

12. When the cross-section of a nozzle increases continuously from entrance to exit, it is called a

Correct : B. divergent nozzle

13. Aeroderivative engines have pressure ratios

Correct : A. greater than 30

14. Aeroderivative engines are larger.

Correct : B. false

15. Aeroderivative engines release higher emissions.

Correct : A. true

16. Critical pressure ratio is ratios of pressures at discharge.

Correct : D. maximum

17. Ratio of critical pressure to inlet pressure in known as

Correct : C. critical pressure ratio

18. In De Laval Nozzle critical pressure ratio is given by (2/y+1)^(y/y-1).

Correct : A. true

19. With the increase in pressure, the exit velocity

Correct : A. decreases

20. The Prandtl Number approximates

Correct : A. momentum diffusivity to thermal diffusivity

21. Pumps increase

Correct : A. pressure

22. Which among the following is the formula for volumetric flow rate?

Correct : B. q = av

23. Which among the following is the formula for mass flow rate?

Correct : B. q = mp

24. Compressible flow mainly deals with

Correct : C. gas dynamics

25. Which among the following is an assumption of the compressible flow?

Correct : B. no-slip condition

26. What is Mach number?

Correct : B. speed of object /speed of sound

27. Which of the following kinetic friction is smaller?

Correct : C. rolling friction

28. A mass of 4kg rests on a horizontal plane. The plane is gradually inclined until at an angle θ= 15° with the horizontal, the mass just begins to slide. What is the coefficient of static friction between the block and the surface?

Correct : B. 0.27

29. A scooter weighs 120kg f. Brakes are applied so that wheels stop rolling and start skidding. Find the force of friction if the coefficient of friction is 0.4.

Correct : B. 48kg f

30. How is friction due to air reduced?

Correct : A. streamlining

31. Friction can be increased by

Correct : C. using sand

32. When moving along a curved path, he

Correct : A. leans inwards

33. A train has to negotiate a curve of radius 400m. By how much should the putter rail be raised with respect to inner rail for speed of 48 km/h? The distance between the rails is 1m.

Correct : B. 0.0454m

34. When a gas is pushed through a pipe, the gaseous molecules are by the pipe’s walls

Correct : C. deflected

35. In fluid dynamics, the velocity of the fluid in the stagnation point is

Correct : A. zero

36. If the speed of sound is much                   than that of the gas, the gas density will stay constant.

Correct : B. larger

37. Isentropic nozzle flow states about the movement of a gas or fluid through a narrow orifice without an increase or decrease in

Correct : B. decelerating

38. To refrain from separation in subsonic nozzles, the expansion angle must not be more than

Correct : A. 10 degrees

39. Gas flows through the nozzle from an area of pressure (called the chamber) to one of pressure

Correct : A. high, low

40. Converging-diverging nozzle is also known as

Correct : D. de laval’ nozzle

41. When the pressure chamber is big, the flow velocities are

Correct : B. negligible

42. For a compressible, ideal gas, mass flow rate depends on parameters such as flow area, pressure, temperature, properties of the gas, and

Correct : B. mach number

43. Which type of boilers use orifice to control the flow circulation?

Correct : B. forced convection boilers

44. What is the advantage of having smaller ratio of water to steam space?

Correct : A. steam can be generated at a faster even if the boiler is cold

45. Which are the major types of boilers that are operated in world today?

Correct : D. once through boiler

46. How many level indicators are there in the water level indicator of a boiler?

Correct : B. 2

47. What is the function of pressure gauge in the boiler?

Correct : A. to indicate steam pressure

48. other than Steam stop valve in the boiler which is the other similar type of valve used?

Correct : D. junction valve

49. What is the function of Blow down valve of a boiler?

Correct : A. to remove sludge

50. What is the function of fusible plug in the boiler?

Correct : A. protect the fire tube

51. What is the function of safety valves in the boiler?

Correct : A. to prevent excessive steam pressure

52. How many types of safety valves are used in boiler in practice?

Correct : B. 2

53. What happens due to high temperature of feeds water in the economizer?

Correct : C. fuel consumption decreases

54. What is the function of superheater in the boiler?

Correct : A. increase the temperature of steam

55. What is the function Air heater in the boiler?

Correct : B. recover the heat from flue gas

56. What is the function of the feed water pump of a boiler?

Correct : A. pump water at high pressure

57. Rotary pumps are driven by

Correct : A. electric motors

58. Which fuel is prepared by heating bituminous coal continuously for 15 to 18 hours in closed chamber?

Correct : C. coke

59. Which fuel is produced by powdering low grade coal with high ash content?

Correct : B. pulverized coal

60. Which is the correct advantage of solid fuels out of the given option?

Correct : A. they have low ignition temperature

61. Choose the proper disadvantage of solid fuels out of the given option?

Correct : A. they produce lot of smoke

62. In what forms are liquid fuels available in nature?

Correct : D. crude petroleum

63. Name the process used to eliminate impurities present in crude oil?

Correct : A. distillation

64. Which fuel is heavier than petrol but less volatile and it is commonly used as domestic fuel?

Correct : C. kerosene

65. Which fuel is slightly heavier than kerosene and is produced in petroleum fractions?

Correct : D. distillate

66. Which fuel has higher thermodynamic efficiency in liquid fuels?

Correct : A. diesel

67. Which liquid fuel has a wider composition than diesel and used in furnaces of oil fired boiler?

Correct : A. fuel oil

68. Which is the artificial liquid fuel obtained by fermentation process?

Correct : B. alcohol

69. Which among the following fuels need excess amount of air for complete combustion?

Correct : D. artificial solid fuels

70. Which of the following is not a type of steam turbine?

Correct : C. pelton wheel turbine

71. Majority of the turbines are axial flow type.

Correct : A. true

72. Which turbines are employed for driving alternator at synchronous speed?

Correct : A. central station turbine

73. Non Condensing steam turbine can also be called as

Correct : B. back pressure steam turbine

74. Steam turbine is classified on basis of

Correct : D. all of the mentioned

75. High pressure turbine is a Non-Condensing turbine due to

Correct : A. exhaust conditions

76. Impulse blades are in the shape of

Correct : C. half moon

77. Astern turbines are used in

Correct : B. marine purposes

78. Cross compound steam turbines are once used in

Correct : B. marine ships

79. When steam reaches turbine blades the type of force responsible for moving turbine blades are

Correct : A. axial force

80. Multi stage arrangement of turbines is called as

Correct : C. compounding

81. Compounding efficiency at low speed.

Correct : B. increase

82. In velocity compounded turbines flow passage is from

Correct : D. none of the mentioned

83. A velocity compounded impulse turbine is also called as

Correct : A. curtis wheel

84. Reaction turbine is also called as

Correct : C. parsons turbine

85. A turbine comprising of fixed blades and moving nozzles is called as reaction turbines.

Correct : A. true

86. Which of these is not an application of back pressure turbine?

Correct : B. filtration of water

87. Pass-out turbines are used in which of these cases?

Correct : D. both relatively high back pressure and small heating requirement

88. Heat exchangers are classified into how many categories?

Correct : D. 4

89. Based upon the nature of heat exchange process, the heat exchangers are classified into how many categories

Correct : C. 3

90. Which type of flow arrangement is this?

Correct : B. parallel flow

91. Which of the following is not an example of recuperators type heat exchanger?

Correct : C. chemical factories

92. In how many categories heat exchangers are classified on the basis of direction of flow of fluids?

Correct : B. 3 categories

93. In how many categories heat exchangers are classified on the basis of physical state of heat exchanging fluids?

Correct : B. 2

94. Which of the following operations occur in a vapour refrigeration cycle?

Correct : D. all of the mentioned

95. Compression can be

Correct : C. both of the mentioned

96. Wet compression is preferred over dry compression.

Correct : B. false

97. Why is wet compression not preferred?

Correct : D. all of the mentioned

98. The expansion process is

Correct : C. adiabatic

99. The evaporation process is a

Correct : B. constant pressure reversible process

100. The evaporator produces the cooling or refrigerating effect.

Correct : A. true