Quiznetik

Thermal Engineering 2 | Set 4

1. Energy recovery is typically via production of __________

Correct : D. steam

2. Which of the following industrial process uses waste as a fuel?

Correct : A. cement kilns

3. What is the combustion temperature range in cement kiln incineration?

Correct : B. 1350-1650

4. Non-volatile heavy metals in kiln are fixed into __________

Correct : A. clinker’s crystalline structure

5. Which of the following waste types are not suitable for co-combustion in cement kilns?

Correct : A. chlorine

6. . Due to the limits, upper efficiency of steam turbines is fixed to _________

Correct : D. 35-45%

7. How many sections does waste heat recovery boiler have in steam generators?

Correct : C. 3

8. Turbines that are run by exhaust gases are called _______

Correct : A. power recovery turbines

9. Combination of two or more thermodynamic processes gives _________

Correct : B. increase in efficiency

10. By using combined cycle steam and gas power plant _________

Correct : C. specific fuel consumption can be decreased and efficiency increased

11. What are turbo-compound engines?

Correct : A. turbines run at exhausts of otto and diesel cycles

12. The mercury steam cycle represents how many coupled Rankine cycles?

Correct : B. 2

13. In the mercury steam cycle, the mercury cycle is called?

Correct : C. topping cycle

14. In the mercury steam cycle, the steam cycle is called?

Correct : A. bottoming cycle

15. Apart from mercury & steam, which of these is a component of tertiary cycle?

Correct : D. sulphur di-oxide

16. The addition of sulphur dioxide in a tertiary cycle is at?

Correct : B. low temperature

17. Which of these can also be used as a topping fluid?

Correct : A. sodium

18. Which of these can be used as a fluid in the bottoming fluid?

Correct : B. ammonia

19. In case of Sodium-mercury-steam cycle, which is the topping fluid?

Correct : C. sodium

20. In case of mercury-steam-sulphur dioxide cycle, which is the bottoming fluid?

Correct : C. sulphur dioxide

21. The total loss in a tertiary cycle is?

Correct : B. product of losses in the individual cycles

22. Room air conditioners and packaged units are examples of _________

Correct : A. direct expansion systems

23. The process of extraction of the certain required amount of water from air is known as ___________

Correct : D. dehumidification

24. The reciprocal of thermal conductivity is known as __________

Correct : D. thermal resistivity

25. Condensers and evaporators together form a ____________

Correct : B. refrigeration system

26. In traditional Refrigerators in home appliances, what is the type of condenser used?

Correct : A. natural convection type

27. In traditional Air conditioners in home appliances, what is the type of condenser used?

Correct : B. forced convection type

28. In evaporative condensers, ___________ used to extract heat from the condensing refrigerant.

Correct : B. both air and water are

29. Evaporative condensers combine the features of a _____________ in a single unit.

Correct : A. cooling tower and water-cooled condenser

30. Evaporative condensers are used in places where water is _________

Correct : A. scarce

31. What is the meaning of heat rejection ratio (HRR) of a condenser?

Correct : A. ratio of heat rejected to the heat absorbed

32. What is the relation between heat rejection ratio (HRR) and Coefficient of performance (COP)?

Correct : A. hrr = 1 + 1/cop

33. Which type of fins are the most commonly used fin type in condensers?

Correct : B. plate type fins

34. Shell and coil type condensers have a capacity at around ________

Correct : D. 50 tr

35. Double pipe water cooling condensers have a capacity at around ________

Correct : A. 10 tr

36. If there is a decrease in viscosity, the heat transfer coefficient ____________

Correct : A. increase

37. An increase in diameter means a _________ heat transfer coefficient.

Correct : B. smaller

38. why is an analyser-rectifier combination is used in absorption refrigeration cycle?

Correct : C. to eliminate the water vapour from ammonia vapour

39. The vapour going to condenser is ____ in temperature and ____ in ammonia.

Correct : D. lower, richer

40. Water is used as a ____ in air conditioning units.

Correct : B. refrigerant

41. The COP of absorption refrigeration system is

Correct : A. low

42. The wet bulb temperature is the ____ temperature recorded by moistened bulb.

Correct : A. lowest

43. When unsaturated air flows over a sheet of water in an insulated chamber

Correct : A. specific humidity of air decreases

44. When humidity ratio of air ____ air is said to be dehumidified.

Correct : B. decreases

45. Cooling towers are rated in terms of

Correct : C. both of the mentioned

46. A nozzle used to send fluid in coherent stream is called as

Correct : A. jet

47. In fountains the type of nozzle used is

Correct : D. laminar jet

48. The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop

Correct : B. decreases

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

Correct : B. nozzle efficiency

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

Correct : D. maximum

51. The exit velocity in the nozzle increases as per

Correct : B. continuity equation

52. Compressible flow is a flow that deals with

Correct : C. fluid density

53. The coefficient of kinetic friction is less than the coefficient of static friction.

Correct : A. true

54. A cubical block rests on an inclined plane of μ = 1/√3, determine the angle of inclination when the block just slides down the inclined plane?

Correct : C. 30°

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

Correct : C. deflected

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

Correct : A. high, low

57. On what basis are fire and water tube boilers are classified?

Correct : D. depending tubular heating surface

58. Stirling boiler is an example of which type of boiler?

Correct : D. water tube boiler

59. Which of these is a stationary boiler?

Correct : D. babcock-wilcox boiler

60. Which of these is a mobile boiler?

Correct : C. locomotive boiler

61. Are boilers defined on the basis of heat source.

Correct : A. yes

62. What is the steam pressure limit of natural circulation boilers?

Correct : B. 180bar

63. Which of the given boilers operate above critical pressure?

Correct : C. once-through boilers

64. Which type of boilers are called drum-less boilers?

Correct : C. positive forced circulation boiler

65. Chances of sediments depositing inside the water tubes in the shell is less due to?

Correct : D. high working pressure

66. Out of the given option choose the advantage that supports fire tube boilers?

Correct : C. water circulation is limited inside boiler shell

67. Tubular air preheater of a boiler is also called as

Correct : A. recuperative air preheater

68. What does regenerative air preheater consists of?

Correct : A. rotor

69. Which fuel is prepared by moulding finely ground coal under pressure?

Correct : C. briquette coal

70. Which fuel has the lightest liquid petroleum fraction?

Correct : B. petrol

71. Which statement about impulse turbine is true?

Correct : B. steam expends completely in stationary nozzels

72. In velocity compounding the steam is expanded from the boiler pressure to condenser pressure in one set of stationary blades on nozzle.

Correct : A. true

73. In condensing turbines vacuum is obtained by

Correct : C. sudden drop in pressure and by removal of non condensable gases

74. Reaction turbine works with the force obtained from change in pressure energy.

Correct : A. true

75. A turbine having alternate blades and nozzles is called as

Correct : A. impulse turbine

76. Compounding                      efficiency at low speed.

Correct : B. increase

77. In pressure compounded turbines moving nozzles are followed by turbine blades.

Correct : B. false

78. In pressure compounded turbines flow passage is from

Correct : B. fixed nozzles to moving blades

79. A plant producing both, electrical power & process heat simultaneously is?

Correct : C. cogeneration plant

80. In a by-product power cycle?

Correct : C. power production is after the cycle has ended

81. In terms of cost per MW compared to condensing sets of the same power, the back pressure turbines are?

Correct : B. cheaper

82. Which of the following is a good medium for constant temperature heating?

Correct : B. steam

83. The cogeneration plant efficiency nCO if WT, Qi, QH represents turbine work, heat input, heat output respectively is given by?

Correct : D. nco = (wt + qh) / qi

84. If e is the electricity fraction of the total energy output, m is the electric plant efficiency and n is the steam generator efficiency; the heat added per unit total energy output is given by?

Correct : A. (1 / m) + ((1 – e) / n)

85. Which of these is not considered economical for cogeneration?

Correct : B. a low fraction of electric to total energy

86. The energy transfer between the hot fluid and cold fluids is brought about by their complete physical mixing in

Correct : A. direct contact heat exchanger

87. In vapour refrigeration cycle, which of the following is used for expansion?

Correct : B. throttling valve or capillary tube

88. Wet compression is preferred over dry compression.

Correct : B. false

89. One tonne of refrigeration is given as the rate of heat removal from surroundings equivalent to heat required for melting one tonne of ice in a day.

Correct : A. true

90. Superheating of vapour and subcooling of liquid          the refrigerating effect.

Correct : B. increases

91. A condenser must          and then          the compressed refrigerant.

Correct : D. desuperheat, condense

92. The vapour going to condenser is          in temperature and          in ammonia.

Correct : D. lower, richer

93. Water is used as a          in air conditioning units.

Correct : B. refrigerant

94. Which of the following types of filters used in the air conditioning system is made of cloth that is discarded on getting dirty?

Correct : B. dry filter

95. Select the disadvantage of cooling pond out of the given?

Correct : C. there is no control over the temperature of cooled water

96. How is water circulated throughout the dry cooling tower system?

Correct : A. finned tubes