Sample Viva Questions of ME Lab-2

Two stage air compressor

1 What is 2 stage compression?

2 What is Volumetric efficiency?

3 What is Isothermal efficiency?

4 What is Overall efficiency?

5 What is intercooler?

6 What happens to the pressure of air before and after the intercooler

7 How does kg/cm2 become the unit of Pressure?

8 How is the amount of air entering into the compressor estimated?

9 Why do we need the digital tachometer?

10 Name the actual process that is happening in the compressor?

11 Why is the isothermal efficiency calculated?

12 Write down the relation for Polytropic work input demanded by compressor.

13 What is orifice meter and why is it used?

14 Why do we use water in manometer if we want to measure air head? Suggest better alternative to water.

15 Why does cooler air come out of the compressor tank if compression increases temperature?

16 Write down the relation for Isothermal work input demanded by compressor. Which temperature is used in this relation?

17 How do you measure the density of air for this experiment?

18 What is the value of R for air?

19 What is coefficient of discharge? Where do we use it?

20 Should the volumetric efficiency decrease or increase with tank pressure? Why?

21 What is polytropic index? How does it influence the compression process?

22 How does the energy input to compressor actually measured?

23 What is energy meter constant?

24 What are the methods that you suggest for increasing the efficiency of compressor?

Performance of Vertical Diesel engine

25 What is meant by load test of vertical diesel engine?

26 List and relate various Power terms used in relation to engine performance.

27 What are the methods that we have for determining the Friction power of the engine?

28 What does FC indicate? How does it vary with load on engine?

29 Define IP. How can we estimate it?

30 What is BTH?

31 What is ITH?

32 What is IMEP, what does it signify?

33 What is BMEP, what does it signify?

34 What happens to FP if engine speed increases or decreases?

35 Write down the relation for IMEP & BMEP.

36 How is BP estimated in this experiment? Write its expression.

37 What is SFC ? How is it related to speed of the engine?

38 What does negative intercept on x axis of FC Vs BP plot denote?

39 What is Willan's line? How should it be constructed?

40 Define Mechanical efficiency of an engine?

41 What does Indicative thermal efficiency depict about the engine?

42 What is your finding about the performance of the vertical diesel engine?

43 What performance plots were prepared to understand the vertical diesel engine? Why?

44 What is the significance of each performance plot prepared in the experiment of vertical diesel engine?

45 What were the performance parameters of the engine?

46 List the specifications of the vertical diesel engine?

47 What are the methods that you suggest for increasing the efficiency of vertical cylinder engine?

48 What is the use of having decompression lever?

Heat Balance Sheet

49 What is a heat balance sheet?

50 List the performance parameters which define the functioning of engine?

51 What is the nature of load applied on the engine while preparing heat balance sheet?

52 What are the different types of applying loads on engine?

53 Why do we require exhaust calorimeter?

54 How can we find the Cp of exhaust gases?

55 Does water flow rate influence the heat transfer? How?

56 Should water be circulated around the cylinder with less flow rate or more flow rate? Why?

57 What is the role of engine's fuel consumption in preparing heat balance sheet?

58 What is phase lag? What does it denote?

59 What are the different component that consume heat generated from the engine?

60 How do we measure the heat lost from the engine due to radiation?

61 Write a relation for estimating BP of an engine for preparing heat balance sheet?

62 List the specifications of the engine on which the heat balance sheet is prepared?

63 What are the additional components (mountings) required for preparing heat balance sheet?

64 What does the term heat equivalent mean? Where do we use it?

65 What are the methods that you suggest for increasing the performance of engine?

66 What is the use of having decompression lever?

Performance of Horizontal Diesel engine

67 What is load test of a horizontal diesel engine?

68 List and relate the power developed at various locations of the engine.

69 In what all ways, the Friction power of the engine determined?

70 What is FC? What happens to it when load on engine varies?

71 What is IP, by what means can we estimate it?

72 What is hBTH?

73 What is hITH?

74 What is IMEP, what does it signify?

75 What is BMEP, what does it signify?

76 What happens to FP if engine speed increases or decreases?

77 Write down the relation for IMEP & BMEP.

78 How is BP estimated in this experiment? Write its expression.

79 What is SFC ? How is it related to speed of the engine?

80 What does negative intercept on x axis of FC Vs BP plot denote?

81 What is Willan's line? How should it be constructed?

82 Define Mechanical efficiency of an engine?

83 What does Indicative thermal efficiency depict about the engine?

84 What is your finding about the performance of the horizontal diesel engine?

85 What performance plots were prepared to understand the horizontal diesel engine? Why?

86 What is the significance of each performance plot prepared in the experiment of horizontal diesel engine?

87 What are the parameters that indicate the performance of an engine?

88 List the specifications of the horizontal diesel engine?

89 What are the methods that you suggest for increasing the efficiency of horizontal cylinder engine?

90 What is the use of having decompression lever?

Kinematic analysis of Slider crank mechanism

91 What is a slider crank mechanism?

92 Write down the expression used for calculating the Velocity of slider.

93 What is graphical differentiation?

94 What is pole point and why is it used?

95 How can we determine velocity by knowing the position?

96 What assumptions have we taken for determining the velocity of slider analytically?

97 List the four links of Slider crank Mechanism in the order of their connection.

98 What is the difference between linkage and mechanism?

99 What are X&Y axes in the displacement and velocity plots?

100 List any two practical applications of Slider crank mechanism.

101 What is the difference between higher pair and lower pair? Give few examples for both

102 What is toggle position? Does slider crank mechanism fall into it?

103 What is the best procedure to construct the tangents in displacement plot?

104 What other methods are available to determine the velocity of a slider?

105 What were your suggestions in simplifying the determination of slider's velocity?

106 What are the reasons for deviation of theoretical values from actual values?

107 What are the possible errors that can incur with the present procedure of finding slider's velocity?

108 What is kinematic analysis?

Kinematic analysis of 4 bar mechanism

109 What is a crank rocker mechanism?

110 How can we determine the velocity of rocker?

111 What is graphical differentiation?

112 What is pole point and why is it used?

113 How can we determine velocity by knowing the position?

114 What assumptions have we taken for determining the velocity of rocker?

115 List the four links of crank rocker Mechanism in the order of their connection.

116 What is the difference between linkage and mechanism?

117 What are X&Y axes in the displacement and velocity plots?

118 List any two practical applications of Crank rocker mechanism.

119 What is the difference between higher pair and lower pair? Give few examples for both

120 What is toggle position? Does crank rocker mechanism fall into it?

121 What is the best procedure to construct the tangents in displacement plot?

122 What other methods are available to determine the velocity of a rocker?

123 What were your suggestions in simplifying the determination of rocker's velocity?

124 What are the possible errors that can incur with the present procedure of finding rocker's velocity?

125 What is kinematic analysis?

Gyroscopic effect

126 What is a gyroscope?

127 What are the three couples that act on gyroscope called?

128 What couple will lie in a plane containing gyroscopic axis and spin plane?

129 What is the expression used for calculating the gyroscopic couple theoretically?

130 What is the expression used for calculating the actual gyroscopic couple of this experiment?

131 What is the probable reason for deviation between theoretical and actual readings?

132 What suggestions do you have for reducing the %error calculated in the gyroscopic couples?

133 List few practical applications of gyroscopic couple.

134 How does a gyroscopic couple created in the experiment?

135 How is the precision couple measured?

136 How does the gyroscopic effect change with increase in q?

137 What happens to precision time, if gyroscopic effect is increased?

138 What is the purpose of using gyroscopic effect in aircrafts?

139 If spinning time is reduced for same number of disc rotations, what happens to gyroscopic couple?

140 What is moment of inertia? Write its relation for disc.

141 What is radius of gyration? Write relation for radius of gyration of disc.

Volumetric efficiency and Air fuel ratio

142 What is meant by volumetric efficiency of an engine?

143 What is meant by air fuel ratio? What is its value for petrol and diesel engines?

144 How do we estimate the amount of air part-taking in combustion?

145 How does the load change influence FC of an engine?

146 How is BP estimated in this experiment? Write its expression.

147 What is your finding about the volumetric efficiency of vertical diesel engine?

148 What performance plots were prepared to understand the volumetric performance of engine? Why?

149 What were the performance parameters of the engine?

150 List the specifications of the diesel engine used for finding volumetric efficiency?

151 What is 3way cock used for?

152 What is the use of having decompression lever?

153 What are the methods that you suggest for increasing the volumetric efficiency of engine?

154 How does air intake change with increase in engine load?

155 What is the expected change in air fuel ratio if engine load is increased? Explain the reason.

156 What is the expected change in volumetric efficiency if engine load is increased? Explain the reason.

157 What is the reason for change in air fuel ratio? Is it because of much change in air intake or fuel intake?

Morse Test

158 What is Morse test?

159 What aspects of engine performance can be estimated using Morse test?

160 What are the methods that we have for determining FP of an engine?

161 What are the limitations of Morse test?

162 Can Morse test be used for single cylinder engines? Provide reasons for your answer.

163 What is the nature of load applied on the engine while conducting Morse test?

164 How is BP of the engine calculated while conducting Morse test?

165 How is total IP of the engine calculated while conducting Morse test?

166 How is FP of the engine calculated while conducting Morse test?

167 What is the reason for decreasing the load on the engine after cutting one of the cylinders off?

168 What made the engine to lower its speed after cutting one of the cylinder?

169 How is the engine speed measured in the experiment of Morse test?

170 What are the other methods available for determining the FP of multi cylinder engine?

171 What were your suggestions to simplify the procedure of Morse test?

Retardation Test

172 What is retardation test?

173 For what sort of engines can the retardation test be used?

174 Do we also have acceleration test? If yes where is it used? If no why?

175 What is the nature of the load applied on the retardation test?

176 Why does we have large flywheel to the engine of retardation test?

177 What is the dependence of size of flywheel to engine speed?

178 What are the methods we have to determine FP of an engine?

179 How is retardation related to engine's performance?

180 How can we measure the retardation of an engine?

181 Can retardation test be used to other engines of this lab? Support your answer with a reason?

182 How is the engine made to retard in retardation test?

183 What is the influence of fuel consumption in the engine's rate of retardation?

184 In your opinion, what is the best way of finding FP of an engine? Why?

185 What maximum load can be applied on the engine? What happens if more load is applied?