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