**Related Resources: Heat Transfer**

### Thermodynamic Applications

White Papers, Engineering Documents & Specifications

Engineering Heat Transfer

Thermodynamics Engineering

Thermodynamic Applications

BY J. E. EMSWILER

Late Professor of Mechanical Engineering University of Michigan

* REVISED BY

F. L. SCHWARTZ Associate Professor of Mechanical Engineering University of Michigan

Fifth Edition

This resource requires a *Premium Membership*

Open: Thermodynamic Applications

PREFACE

Earlier editions of “ Thermodynamics” by the late Professor J. E. Emswiler of the University of Michigan were received with such general approval it seemed unadvisable not to offer a new edition with some additions and revision necessitated by recent developments in the presentation of the subject. The lucid explanations, numerous illustrative examples, free use of diagrams and graphical representations in earlier editions have been retained. Some rearrangement of the material has been made. The general case has been presented before the specific. The several phases of the working substance are presented in general and vapors and gases are considered subsequently. The polytropic process for gases is presented in detail and followed by the adiabatic, isothermal, constant volume and constant pressure proc- esses as special applications of the polytropic. More emphasis on gases and the general energy equation for steady flow processes appears in the new edition than in former editions. Throughout this edition American Standards Association symbols and abbreviations have been used. New material on absorption refrigeration, gas turbines, gas cycles, adiabatic saturation of air-water vapor mixtures, and supersaturation has been added. The author of the revision wishes to thank his associates in the department of Mechanical Engineering in the University of Michigan for their interest and constructive criticism of the revised edition.

TOC

CHAPTER I.—'THERMODYNAMICS

1. Definition of Thermodynamics 1

2. Sources of Energy 1

3. The Study of Thermodynamics 2

CHAPTER II.—ENERGY

4. The Kinetic Theory of Gases 3

5. Forms of Energy * 7

6. Heat 7

7. Work 10

8. Power 12

9. Work and Power Units 12

10. Flow Work 12

11. Kinetic Energy 14

12. Potential Energy 14

13. Internal Energy 15

14. Other Forms of Energy 16

15. Properties or Point Functions, Energy Transfers or Line Functions 17

CHAPTER III.—FIRST LAW OF THERMODYNAMICS

16. First Law of Thermodynamics 20

17. General Energy Equation 20

18. Enthalpy 21

19. Applications of the General Energy Equation 21

20. Steady-flow and Nonflow Processes 23

21. General Energy Equation for Nonflow Processes 24

CHAPTER IV.—POWER PLANTS

22. The Steam Power Plant 27

23. The Internal Combustion Engine Power Plant 28

24. The Essential Elements of a Heat Engine 29

25. A Compressed-air System 29

26. The Refrigerating Plant. . . 30

CHAPTER V.—WORKING SUBSTANCES

27. Change of State Accomplished by Heating a Substance .... 33

28. Gases and Vapors 37

29. The Pressure-volume Diagram 38

30. The Pressure-volume Diagram, Neglecting Water Volumes ... 40

31. Significance of Area on the pV Diagram 41

32. Entropy 42

33. The Temperature-entropy Diagram 42

34. Representation of Changes of State of the Steam 43

35. Vapor Tables 45

36. The Entropies of the Steam Tables 49

37. Structure of the Mollier Diagram 51

38. Diagrams 53

CHAPTER VI.—SECOND LAW OF THERMODYNAMICS

39. Insufficiency of the First Law 57

40. The Thought Underlying the Second Law 57

41. The Second Law of Thermodynamics 58

42. Derivation of the Expressions (Ti -* T2 )/Ti and T*/Ti 58

43. Reversible and Irreversible Isothermal Operations 60

44* Reversible and Irreversible Adiabatics 62

45. Other Illustrations of Reversibility and Irreversibility 64

46. An Irreversible Operation Means Loss of Available Energy . * . 65

47. The Carnot Cycle Represents the Highest Possible Efficiency . . 67

48. Other Reversible Cycles 69

49. Availability of Energy Is Continually Decreasing 69

50. Illustration of the Continual Decrease of Available Energy ... 70

51. The Heat of Combustion—Zero Air Excess 70

52. The Heat of Combustion—50 Per Cent Air Excess 72

53. The Enthalpy of the Steam 73

54. Transformation of Heat into Work 75

55. The Enthalpy in the Condenser Cooling Water 75

56. Dissipation of Heat to the Atmosphere 76

57. Loss of Availability in Heat Transfer 78

58. The Single-effect Evaporator 79

59. The Multiple-effect Evaporator 80

60. Useful Output 81

61. Conservation of Availability by Multiplication of Effects .... 83

62. Entropy, a Measure of Unavailability • . . 85

CHAPTER VII.—CYCLES FOR VAPORS

63. Performance of an Actual Steam-heat Engine 88

64. Need of a Standard or Ideal Cycle 89

65. Rankine Cycle 89

66. Comparison of Actual Cycle with Ideal 90

67. The Rankine Cycle on the Pressure-volume Plane 92

68. The Rankine Cycle on the Enthalpy-entropy Plane 93

69. Efficiency of the Rankine Cycle 93

70. Work Area on Temperature-entropy Diagram 96

71. Other Ideal Cycles 97

72. Available and Unavailable Energy . . * 99

73. Utilization of Available Heat 100

74. Disposition of Energy in Utilizer 101

75. How Availability of Heat May Be Lost 103

76. Available-heat Transformations in a Simple One-stage Turbine . 104

77. Return of Energy Losses to the Steam 105

78. Limits of Exhaust State and Relation to Efficiency 107

79. The Turbine of Zero Efficiency. 108

80. The Throttling Calorimeter 110

81. Throttling. . 111

82. Losses in a Steam-engine Cylinder 113

83. Initial Condensation and Reevaporation 114

84. Why Initial Condensation and Reevaporation Result in a Loss of Availability of Energy 115

85. How Initial Condensation and Reevaporatiori Loss Is Reduced by Compounding 117

86. The Uniflow Engine 118

87. Means of Increasing the Efficiency of the Ideal Cycle 119

88. Low Exhaust Temperature 120

89. High Pressure without Superheat 121

90. High Temperature with Moderate Pressure 122

91. Resuperheating 123

92. Extraction Heating of Feed Water 126

93. The Binary Vapor System—Mercury and Steam 131

94. Summary 134

CHAPTER VIII.—PERFECT GASES

95. Relation among the Properties of Gases—Boyle's and Charles's Laws 142

96. Graphical Representation of Charles's Law—Absolute Zero of Temperature . 143

97. Characteristic Equation of a Gas 143

98. The Value of I? 145

99. Perfect Gas 146

100. Specific Heat at Constant Volume and at Constant Pressure . . 146

101. Constant-volume and Constant-pressure Lines on the Temperature-entropy Plane 148

102. Joule's Law . . . 149

103. Deviations from Joule's Law . 151

104. Internal Energy of a Perfect Gas 151

105. Enthalpy of a Perfect Gas .152

106. The Zero of Enthalpy and Entropy for a Gas 153

107. Entropy Change of a Gas . 154

108. Available Heat of a Gas 155

109. Polytropic Processes 156

110. Determination of the Value of n from an Actual Compression Line 159

111. Derivation of the Equation of the Beversible Adiabatic, pVk = Constant 159

112. Adiabatic Processes 160

113. Isothermal Processes 163

114. Constant-pressure Processes 164

115. Constant-volume Processes 165

116. Throttling of Gases 166

117. Throttling from an Unsupplied Reservoir 167

118. Experimental Means of Determining k 168

119. Summary 169

CHAPTER IX.—COMPRESSION AND EXPANSION OF GASES

120. The Compression of Air 176

121. “ Suction ” of a Compressor 177

122. Compression 178

123. Delivery of the Compressed Air 179

124. The Net Work of the Cycle 180

125. Expressions for the Net Work of the Cycle 181

126. Water-jacketing of Air Compressors 183

127. Interstage Cooling of Air Compressors 184

128. Clearance in Air Compressors 186

CHAPTER X.—CYCLES FOR GASES

129. The Internal-combustion Engine 193

130. The Otto Cycle ‘ 193

131. Pressure-volume and Temperature-entropy Diagrams of the Otto Cycle 195

132. Efficiency of the Otto Cycle 197

133. The Diesel Cycle 200

134. Efficiency of the Diesel Cycle 201

135. The Low-compression Oil Engine 202

136. Diesel and Otto Cycles Compared 203

137. The Dual-combustion Cycle 204

138. The Brayton Engine 206

139. Efficiency of the Brayton Cycle 207

140. The Gas Turbine 209

141. The Lenoir Cycle 210

142. The Heat-rejection Line 211

143. Effect of Throttling on the Otto-cycle Engine 212

144. Supercharging 213

145. Nature of Losses in an Otto-cycle Engine 215

146. The Stirling “ Hot-air” Engine, * 217

147. The Cycle of the Stirling Engine 218

148. The Ericsson Hot-air Engine 219

149. The Cycle of the Ericsson Engine 220

150. Comparison of Gas Cycles 221

CHAPTER XI.—REFRIGERATION

151. The Air Refrigerating Machine 226

152. Diagrams for the Air Refrigerating Machine 227

153. The Ammonia Compression Machine 229

154. The Properties of Anhydrous Ammonia 230

155. Representation of Cycle on the Temperature-entropy Plane . . 232

156. Heat Quantities 234

157. Work of the Cycle 235

158. Refrigerating Capacity 236

159. The Refrigerating Coil 236

160. How Low Temperature Is Attained 237

161. The Maintenance of Low Temperature 239

162. Recovery of the Vapor 240

163. Pressures in the System . s 241

164. Refrigerants 242

165. Steam (H20) as a Refrigerant 244

166. The Ammonia Absorption Machine 246

167. The Solution Circuit - 247

168. Temperatures and Pressures of the Solution 248

169. Properties of Aqua-ammonia 249

170. Heat of Solution 251

171. Weight of Solution per Pound of Ammonia 252

172. Heat Liberated in Absorber 253

173. Heat to Be Supplied in Generator 253

CHAPTER XII.—MIXTURES OF GASEOUS SUBSTANCES

174. Weight and Volume Relations 257

175. Specific Heats of Mixtures 260

176. Mixture of Air and Water Vapor 261

177. Dew Point and Saturation Point 262

178. Humidity 263

179. Definition of Terms 265

180. Evaporation vs. Boiling 266

181. The Wet-bulb Temperature 268

182. Steam Associated with 1 Lb of Dry Air 270

183. Adiabatic Absorption of Moisture 271

184. Enthalpy of Steam-air Mixtures 272

185. The Psychrometric Chart 274

186. Approximate Derivation of Carrier's Equation 277

187. Compression of Air-steam Mixture 279

188. The Transformation of Available Energy into the Kinetic Form . 285

189. The Equation of the Nozzle ' 285

190. The Equation of the Continuity of Mass 285

191. General Form of Nozzle Passage 286

192. The Critical Pressure of a Gas 287

194. Critical-pressure Ratio for Various Gases 293

195. The Pressure at the Throat of a Nozzle 294

196. Convergent vs. Divergent Nozzle 294

197. Practical Forms of Nozzles 295

198. Acoustic Velocity in a Nozzle 298

199. Rate of Flow through a Nozzle—General Equation 299

200. Flow through a Nozzle—Back Pressure Less than Critical Pressure 299

201. Flow through a Nozzle—Back Pressure Greater than Critical Pressure 301

202. Example of Steam-nozzle Calculation 303

203. Flow through Orifices 305

204. Supersaturation 306

CHAPTER XIV.—KINETIC ENGINES. THE STEAM TURBINE AND THE INJECTOR

205. Kinetic vs. Direct-pressure Engines 311

206. The Impulse vs. the Reaction Principle 312

207. Classes of Impulse Turbines 313

208. Energy Changes in a Single-pressure-stage Turbine 313

209. Energy Changes in a Multiple-pressure-stage Turbine 315

210. The Reaction Turbine 319

211. The Steam Injector 320

212. Impact 322

213. Efficiency of the Injector 323

Index 327

Mollier Diagram 338

Steam Tables

Mean Specific Heats of Superheated Steam 339

Properties of Saturated Steam 340

Properties of Superheated Steam . 344