A Textbook of Thermal Engineering

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R.S. KHURMI, J.K. GUPTA

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2 نوفمبر 2022

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هندسة الإنتاج والتصميم الميكانيكى, هندسة السيارات, هندسة القوى الميكانيكية

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A Textbook of Thermal Engineering
[A Textbook for the Students ofB.Sc. Engg., UPSC (Engg. Services), Section ‘B’ ofAMIE (I) and Diploma Courses]
(S.I. UNITS)
R.S. KHURMI, J.K. GUPTA
CONTENTS

Introduction 1
Properties of Perfect Gases 30
Thermodynamic Processes of Perfect Gases 50
Entropy of Perfect Gases 103
Kinetic Theory of Gases 140
Thermodynamic Air Cycles 153
Formation and Properties of Steam 199
Entropy of Steam 219
Thermodynamic Processes of Vapour 230
Thermodynamic Vapour Cycles 264
Fuels 289
Combustion of Fuels 301
Steam Boilers 323
Boiler Mountings and Accessories 334
Performance of Steam Boilers 345
Boiler Draught 360
Simple Steam Engines 374
Compound Steam Engines 394
Performance of Steam Engines 422
Steam Condensers 446
Steam Nozzles 469
Impulse Turbines 501
Reaction Turbines 521
Performance of Steam Turbines 535
Modern Steam Turbines 560
Internal Combustion Engines 582
Testing of Internal Combustion Engines 611
Reciprocating Air Compressors 637
Rotary Air Compressors .. 665
Performance of Air Compressors 682
Air Motors 700
Gas Turbines 707
Performance of Gas Turbines 721
Introduction to Heat Transfer 736
Air Refrigeration Cycles 751
Vapour Compression Refrigeration Systems 771
Psychrometry 798
Air Conditioning Systems 824
General Thermodynamic Relations 835
Variable Specific Heat 859
Index 887
Index
Absolute humidity, 799, 800, 801

pressure, 12
temperature, 11
units of force, 7
Actual gas turbine, 725
indicator diagram, 381, 588, 590, 593,
595
vapour compression cycle, 789
Adiabatic compressibility, 842
process, 63
mixing of two air streams, 819
saturation temperature, 806
Advantages of compoundingof steam engines,
395
condensers in a steam power plant, 446
mechanical draught, 361
multistage compression, 647
reheating of steam, 561
steam turbinesover reciprocating steam
engines, 501
superheating of steam, 206
two stroke cycle over four stroke cycle
engines, 586
vapour absorption refrigeration system
over vapour compression refrigeration
system, 792
vapour compression refrigeration sys
tern over air refrigeration system, 771
Air conditioning system, 825
consumption, 626
cooling system, 602
injection method, 600
preheater, 340
pump, 464
refrigeration cycle, 751
refrigerator working on Bell Coleman
cycle, 761
on reversed Carnot cycle, 755
standard efficiency, 617
Ammonia hydrogen refrigerator, 793
Anthracite coal, 290
Application of first law of thermodynamics to a
nonflow process, 51
to a steady flow process, 86
of kinetic energy to laws of perfect
gases, 146
of steady flow energy equation to
engineering system, 92
Approximate method for heat absorbed, 135
Artificial draught, 360
Arrangement of cylinders in compound steam
engines, 394
Assumptions for overall (thermal) efficiency of
an ideal gas turbine cycle, 721
in thermodynamic cycle, 153
in kinetic theory of gases, 140
in two stage compressor with inter
cooler, 648
Atomic mass, 301
Atomiser, 608
Atmospheric air, 861
Atoms and molecules, 301
Axial flow compressors, 677
Available heat energy, 105
Average piston speed, 377
Avogadro’s law, 35
B
Babcock and Wilcox boiler, 329
Back flow in positive displacement air compressors, 668
Back pressure turbine, 577
Balanced draught, 362
Barometric jet condensers, 449
Barrel calorimeter, 211
Benson boiler, 331
Binary vapour cycle, 577
plant, 567
Bituminous coal, 290
Blading efficiency, 535
Blast furnace gas, 292
Bleeding, 570
Blow off cock, 338
Boiler accessories, 323,340
efficiency, 346
mountings, 323, 334
shell, 323
trial, 351
Bomb calorimeter, 295
Boyle’s law.30
Boy’s gas calorimeter, 296
Brake power, 389,615
thermal efficiency, 423,616
Brayton cycle, 761
Briquetted coal, 290
Brown coal, 290
By-pass factor, 813,815
887888 A Text book of Thermal Engineering
Caking bituminouscoal, 290
Calorific value of fuels, 293
Carburettor, 606
Carnot cycle, 157, 264
Celsius or centigrade scale, 10
flow surface condenser, 451 .
Centrifugal compressor, 670
Cetane number, 598
C.G.S. units, 2
Change of entropy of a perfect gas, 110
during reversible adiabatic process, 124
constant pressure process, 115
constant temperature process, 120
constant volume process, 110
in thermodynamic properties with variable specific heat, 864
isentropic process, 124
polytropic process, 126
Characteristic equation of a gas, 33
Charles’law, 31
Chimney draught, 360
Classification of air compressors, 637
air conditioning systems, 825
compound steam engines, 395
of draughts, 360
fuels, 289
gas turbines, 708
I.C. engines, 583
properties of a system, 8
steam boilers, 324
steam condensers, 447
steam engines, 374
steam turbines, 502
thermodynamic cycles, 158
thermodynamic process, 51
thermodynamic systems, 7
Clausius statement, 22
inequality, 106
Clearance volume, 156, 377
Closed air refrigeration cycle, 755
cycle gas turbines, 708
system of thermodynamics, 7
Coal gas, 291
Cochran boiler, 326
Coefficient of performance, 752
volume expansion, 841
Coil ignition system, 599
Coke, 290
oven gas, 292
Combined air compressor and air motor, 701
indicator diagram for a compound steam
engine, 397
separating and throttling calorimeter,
214
velocitytrianglefor movingblades of an
impulse turbine, 505
of a reaction turbine, 524
Combustion chamber, 323
equations of gaseous fuels, 303
-of solid fuels, 302
Comfort air conditioningsystem, 825
Comparison between air cooling and water
cooling-system, 603
centrifugal and axial flow air compres
sors, 677
closed and open cycle gas turbines, 718
forced draught and induceddraught, 361
gas turbines and I.C. engines, 708
impulse turbines and reaction turbines,
522
-jet and surface condensers, 452
petrol and diesel engines, 592
reciprocating and centrifugal air com
pressor, 665
steam engines and I.C. engines, 582
turbine and centrifugal compressor
blades, 697
water tube and fire tube boilers, 332
Components of I.C. engine, 584
Compounds, 301
Compound steam engine, 394
Compounding of impulse steam turbines, 552
Compressed air system, 701
Compressibility factor, 856
Compression ratio, 156,538
Compressor capacity, 638
efficiency, 682
Condenser efficiency, 458
Condition for maximum discharge through the
nozzle, 476
efficiency of an impulse turbine, 545
efficiency of a reaction turbine, 548
maximum discharge through the chim
ney, 366
connecting rod, 376, 585
Constant enthalpy process, 84, 92
entropy process, 63, 247
internal energy process, 84
pressure gas turbines, 719
pressure lines, 225
pressure process, 57, 238
temperature process, 61, 242
total heat process, 91, 257
volumegas turbines, 719
volume lines, 225
volume process, 54, 231Index 889
Convergent nozzle, 469
divergent nozzle, 469
Conversion of volumetric analysis into mass
analysis, 307
mass analysis into volumetricanalysis,
307
Cooling and duhumidification, 817
of I.C. engines, 601
systems of I.C. engines, 602
towers, 465
Cornish boiler, 328
Counterflow jet condensers, 448
Crank case, 585
-shaft, 376, 585
Critical pressure ratio, 476
Physical significance of, 479
Values of, 479
Cross head, 376
Cyclic process, 9
Cylinder bore, 156, 377
dimensionsfor compound steam engine,
398
head of I.C. engines, 584
of steam engines, 375
Cushion steam, 429
Cut off governing of compound steam engines,
440
of simple steam engines, 439
volume, 377
D
Dalton’s law of partial pressure, 452, 800
Dead centres, 377
weight safety valve, 336
Degree of reaction, 525, 678
saturation, 799, 800
Degrees of freedom, 148
Dehumidification, 816, 817
De-Laval impulse turbine, 502
Demerits of gaseous fuels, 292
liquid fuels, 291
Dense air regrigeration cycle, 755
Derived units, 2
Detonation in I.C. engines, 597
Dew point temperature, 799
depression, 799
lines, 810
Deagram efficiency, 535
factor, 382
Diameters of throat and exit of a nozzle for
maximum discharge, 481
Diesel cycle, 178
Difference between a heat engine, refrigerator
and heat pump, 753
Disadvantages of mechanical draught, 361
two stroke over four stroke cycle en
gine, 586
-vapour compression refrigeration system
over air refrigeration system, 771
Discharge pressure, 638
Divergent nozzle, 469
Down flow surface condenser, 450
D’slide valve, 375
Dry air, 798
bulb temperature, 799
bulb temperature lines, 809
saturated steam, 200
Dryness fraction lines, 224
of steam, 201
Dual combustion cycle, 188
E
Eccentric, 376
rod, 376
Economiser, 340
Edward’s air pump, 464
Effect of variable specific heat in I.C. engines,
872
on Otto cycle, 872
on Diesel cycle, 879
Effects of air leakage, 464
friction on the velocity diagram of an
impulse turbine, 507
piston rod in a double acting steam en
gine, 387
supersaturation, 491
Efficiencies of a compressor, 682, 693
multistage turbine, 564
steam engine, 422
steam turbine, 564
Efficiency of compressed air system, 702
chimney, 370
cycle, 157
heat exchanger, 730
modified Rankinecycle, 277
ratio, 267, 565
Ejector condensers, 449
Electrolux refrigerator, 793
Elements, 301
Symbols for, 302
Equations of state, 854
Energy, 13
Law of conservation of, 15
Enthalpy of gas, 39
entropy (h-s) diagram for water and”
steam, 223
lines, 810890 A Text book of Thermal Engineering
moist air, 803
steam, 202
Entropy, 103
importance of, 104
increase during evaporation, 220
of superheated steam, 220
of water, 219
of wet and dry steam, 220
Principle of increase of, 107
Units of, 106
Equipment used in air conditioning system, 825
Equaility of temperature, 11
Equivalence of Kelvin-Plank and Clausius
statements, 23
Equivalent evaporation, 345
Ericsson cycle, 166
Essentials of a good steam boiler, 324
Evaporative condenser, 451
Excess air, 310
Mass of, 310
Exhaust ports, 375
turbine, 578
Experimental determination of higher calorific
value, 294
Extensive properties of thermodynamics, 9
External work done during evaporation, 207
Extraction turbine, 57.8
F
Factors affecting comfort air conditioning,824
Fahrenheit scale, 11
Fan draught, 360
Feed check valve, 339
pump, 340
First law of thermodynamics, 19
limitations of, 20
Flow of steam through nozzles, 470
process, 86
Flue gas analysis by Orsat apparatus, 319
Flywheel, 376,585
Force, 6
Forced draught, 361
lubrication, 604
Formation of steam, 199
Fourier’s law of heat conduction, 737
Four stroke cycle diesel engine, 589
gas engine, 591
petrol engine, 587
F.P.S. units, 2
Free air delivery, 638
expansion process, 83
Frame of steam engine, 375
Friction in a nozzle, 470
Fuel pump, 607
Fundamental units, 1
Furance, 323
Fusible plug, 339
Future power plants, 579
G
Gas turbine with intercooling, 711
with reheating, 713
uses of, 733
Gauge pressure, 12
Gaseous fuels, 291
Gasoline, 291
Gay-Lussac law, 31
General equations of change in internalenergy,
843
General expression for the change of entropy of
a perfect gas, 108
gas equation, 31
law for expansion and compression of
perfect gas, 85
Gibbs function, 837
Governor, 376
Governing of I.C. engines, 605
steam engines, 437
steam turbines, 55
simple steam engines, 438
Grate, 323
Gravimetric analysis, 307
Gravitational units of force, 7
Gross calorific value, 293
efficiency, 536
Guide mechanism, 521
H
Heat, 15,17
absorbed or rejected during poly tropic
process, 61
balance sheet, 352,433,628
capacity, 16
exchanger, 729
losses in a boiler, 351
rejected in a reciprocating air compres
sor, 656
transfer by conduction through a slab,
737
transfer during a process with variable
specific heat, 862
during polytropic expansion or com
pression process, 863
through a composite wall, 739
through thick cylinders, 741
through thick sphere, 744
Heating and humidification, 818
Heavy fuel oils, 291Index 891
Height of blades for reaction turbine, 527
chimney, 362
Helmholtz function, 835
Higher calorific value, 293
Experimental determination of 294
High level jet condensers, 449
steam law water safety valve, 336
Humidification,816,818
Humidity, 799,800
lines, 883
ratio, 800
Hyperbolic process, 60,244
Hypothetical indicator diagram, 378
mean effective pressure, 379
I
Ignition system of petrol engines, 598
Indicated mean effective pressure, 611
-power, 383,612
thermal efficiency, 423,616
Indicator diagram of a simple steam engine,
378
Induced draught, 361
Industrial air conditioning system, 826
Injector, 608
Inlet ports, 375
pressure, 637
Inner dead centre, 377
Intensive properties of thermodynamics, 9
Intercooling, 760
of air in a two-stage reciprocating air
compressor, 648
Internal energy, 14
-of steam,208
efficiency, 564
losses in turbine, 555
International system of units, 2
Importance of entropy, 104
Important terms used in steam, 200
thermodynamic cycles, 156
for steam boilers, 323
Impulse turbine, 502
Irreversible cycle, 154
process, 50
Isentropic process, 63,247
efficiency, 683
expansion with variable specific heat,
869
-lines, 223,226
Isobaric process, 57,238
Isochoric process, 54,231
Isothermal compressibility,842
lines 223,226
efficiency, 682
process, 61,242
Jet condensers, 447
Joule’s cycle, 168
law, 32
Joule Thomson coefficient, 92,852
K
Kelvin, 3
Kerosene, 291
Kilogram, 3
Kinetic energy, 14
per kg molecule of a gas, 143
L
La-Mont boiler, 330
Lancashire boiler, 327
Latent heat of vaporisation, 202
Law of conservation of energy, 14
equipartition of energy, 14
perfect gases, 30
thermodyamics, 19
Lever safety valve, 335
Lignite, 290
Limitations of first law of thermodynamics, 20
Liquid fuels, 290
Locomotive boiler, 328
Loeffler boiler, 331
Lower calorific value, 293
Low leveljet condenser, 448
-pressure turbine, 578
Lubrication of I.C. engines, 604
M
Magneto ignitionsystem, 600
Main components of I.C. engines, 584
Mass, 6
Atomic, 301
of carbon in flue gases, 308
of cooling water required for condensa
tionof steam, 460
of excess air supplied, 310
fuel gases per kg of fuel burnt, 308
of steam discharged througha nozzle,
474
of steam in the engine cylinder, 420
–Molecular, 302
Mathematical Fundamentals, 839
Maximum discharge through nozzle, 477
throughchimney, 366
Maxwell’s equation,840
Mean effective pressure, 156,378,638
Measurement of brake power, 389
dryness fraction of steam, 211
vacuum in a condenser, 453892 A Text book of Thermal Engineering
Mechanical draught, 360
efficiency, 422, 616
equivalent of heat, 16
Mechanism of simple vapour compression refrigeration system, 772
Merits of gaseous fuels/292
liquid fuels, 291
Metastable flow through nozzles, 490
Methods of governing I.C. engines, 605
heat transfer, 736
reducing missing quantityor cylinder
condensation, 431
reducing rotor speeds, 552
Metre, 3
Minimum mass of air required for complete
combustion, 304, 306
work required for a two stage compressor, 652
Missing quantity, 430
Mixture qf air and steam in condensers, 452
M.K.S. units, 2
Modified Rankine cycle, 277
Efficiency of, 278
Moist air, 799
Moisture content, 800
lines, 809
Molar constant, 36
specific heat of a gas, 39, 859
Molecular mass, 302
Molecules and atoms, 301
Mollier chart, 223
Mand gas, 292
Morse text, 613
Mountings, 323, 334
Multistage compression, 647
turbine, 563
N
Natural draught, 360
Net calorific value, 293
Newton’s law of cooling, 736
motion, 5
Non-caking bituminous coal, 290
Non-flow process, 51
Application of first law of thermody
namics to, 51
Normal temperature and pressure (N.T.P.), 13
Nozzle efficiency, 470, 536
O
Octane number, 598
Open air refrigerationcycle, 754
cycle gas turbines, 717
system ofthermodynamics, 8
Orsat apparatus, 319
Otto cycle, 1.71
Outer dead centre, 377
Oven gas, 292
Overall coefficient of heat transfer, 746
efficiency, 422, 565, 616, 721
isothermal efficiency, 683
P
Paraffin oil, 291
Parallel flow jet condensers, 448
Parson’s reaction turbine, 521
Pass-out turbine, 578
Path of change of state, 9
Peat, 289
Percentage humidity, 800
Performance criteria for thermodynamic vapour
cycles, 267
Perpetual motion machine of the first kind
(PMM-I), 20
second kind PMM-II), 21
Physical significance of critical pressure ratio,
479
Piston, 375, 585
displacement volume, 377
rings, 585
rod, 375
Polytropic index, determination of, 82
process, 72, 253
Potential energy 14
Power, 18
produced by compound steam engine
398
impulseturbine, 505
reaction turbine, 524
required to drive a compressor, 642, 651
required to drive a fan, 369
simple steam engine, 383
Preheating of compressed air, 704
Presentation of units and their values, 3
Pressure, 12
and velocity of steam in turbine, 503,
522
compoundingof an impulse turbine,
553
enthalpy chart, 773
exerted by an ideal gas, 142
gauge, 335
of water vapour, 801
velocity compounding of an impulse
turbine, 554
Prewhirl, 676
Principle of increase of entropy, 107
Producer gas, 292Index 893
Prony brake dynamometer, 389
Properties of a refrigerant, 793
system, 8
Psychrometer, 799
Psychrometric chart, 809
processes, 812
relations, 800
-terms, 798
Pulverised coal, 290
Q
Quality of wet steam, 201
Quasi-equilibrium or Quasi-static process, 9
R
Rankine cycle, 268
with incomplete evaporation, 272
with superheated steam, 274
efficiency, 565
Rate of heat absorpotion or rejection per unit
volume during a polytropic process, 81
Rating of C.I. engine fuels, 598
S. I. engine fuels,598
.Ratio of coefficient of volume expansion and
isothermal compressibility, 843
cylinder diameters, 658
specific heats, 43, 149
Receiver type compound steam engine , 397
Recent trends in gas turbines, 734
Refrigerants commonly used in practice, 794
Regenerative cycle, 569
with single feed water heater, 570
with two feed water heaters, 573
surface condenser, 451
Regnault’s law, 42
Reheat cycle, 561
factor, 563
Reheating of steam, 560
advantages of, 561
Relation between cycle and engine, 155
heat and entropy, 103
specific heats, 42
Relative efficiency. 423, 617
humidity, 799, 800
humidity lines, 811
Requirements of a steam condensing plant, 446
-good fuel, 292
Reversed Carnot cycle, 755
Joule cycle, 761
Reversible adiabatic process, 247
cycle, 154
process, 50
Reversibility and irreversibility of thermodynamic processes, 155
Roots blower compressor, 666
Rope brake dynamometer, 390
Rules for S.I. units, 4
S
Safety valves, 335
Saturated air, 799
Scavenging of I.C. engines, 596
Scotch marine boiler. 326
Second, 3
law of thermodynamics, 20
Selection of a steam boiler, 324
Semiclosed cycle gas turbine, 719
Sensible cooling, 812
heat factor, 816
heating, 814
heat of water, 201
Separating calorimeter, 213
Sequence of operations in a cycle, 585
Simple vertical boiler, 325
S.I. Units, 2
Single stage reciprocating air compressor, 638
Slip factor, 697
Solid fueld, 289
injection method, 600
Spark plug, 607
splash lubrication, 604
Sources of air in the condenser, 464
Specific heat, 15, 37, 850
at constant pressure, 37
at constant volume, 38
humidity, 800
humidity lines, 809
ratio of, 43
relations, 851
relation between, 42
steam consumption, 267
volume lines, 810
volumeofsteam, 202
Spring loaded safety valve, 337
State of a system, 9
Standard temperature and pressure (S.T. P.), 13
Static and total head quantities, 695
Steady flow process, 86
Workdone in a, 89
Steam consumption, 440
-chest, 375
injector, 493,494
jet draught, 361
stop valve, 338
tables, 203
Stirling cycle, 164
Stored energy, 13
Types of, 14894 A Text book of Thermal Engineering
Stroke length, 156
volume, 377
Summary of formulae of heating and expansion
of perfect gases, 85
Summer air conditioning system, 829
Supercharging of I.C. engines, 603
Superheated steam, 201,206
Supersaturated flow through nozzles, 490
Surface condenser, 449
Swept volume, 156,377,638
Symbols of elements and compounds, 302
System of units, 2
T
Tandem type compound steam engine, 395
T ds equations, 847
Temperature, 10
entropy diagram for water and steam,
222
gradient, 738
limitations for reversed Carnot cycle,
756
vs total heat graph during steam formation, 200
Theroretical indicator diagram of simple steam
engine, 378
mass of air required for complete com
bustion, 304, 306
mean effective pressure, 379
vapourcompression cycle with dry
saturated vapour after compression,
774
with superheated vapour after compres
sion,783
with undercooling or subcooling of re
frigerant, 785
with wet vapour after compression, 778
Thermal capacity, 16
conductivity, 737
equilibrium, 11
Thermodynamic cycle,9
assumptions in, 153
equilibrium, 11
for rotary air compressor, 693
Important terms used in, 156
systems, 7
text of I.C. engines, 611
wet bulb temperature, 806
Thermosyphon system of cooling, 602
Three cylinder compound steam engine, 414
Throttle governingof compound steamengine,
414
Throttle governing of compound steam engines, 439
simple steam engines, 438
steam turbines, 555
Throttling calorimeter, 213
lines, 226
process, 91,257
Total heat lines, 810
of moist air, 803
of steam, 202
Transit energy, 13
Two cylinder compound steam engine, 399,
401,407
stage reciprocating air compressor, 647
stroke cycle diesel engine, 594
stroke cycle petrol engine, 592
Types of cooling towers, 465
draughts, 360
-jet condensers, 448
rotary air compressors, 665
scavenging, 597
steam nozzles, 469
stored energy, 14
surface condensers, 450
thermodynamiccycles, 157
vapour compression cycles, 773
U
Unavailable heat energy, 105
Unitary air conditioning system, 830
Units of entropy, 106
refrigeration, 752
Universal gas constant, 36
Unresisted expansion process, 83
Uses of gas turbines, 733
steam tables, 203
Vacuum efficiency of steam condenser, 453
Values for maximum discharge through a nozzle, 477
of critical pressure ratio, 479
Valve timing diagrams, 587,589,591,594,596
Vane blower compressor, 667
Vander Waals’ equation of a real gas, 150
Vapour absorption refrigeration system, 791
compression cycles, 773
pressure lines, 811
Variation of specific heat with temperature,860
Velocity compounding of an impulse turbine,
552
diagram for axial flow air compressor,
678
diagram for moving blade of an im
pulse turbine, 503Index 895
diagram for two stage impulse turbine,
514
of a molecule, 141
of steam flowing through a nozzle, 471
triangle for centrifugal compressor, 673
triangle for moving blades of a reaction
turbine, 522, 524
Vertical multi-tubular boiler, 326
Volumetric efficiency, 617, 683, 684
W
Water cooling system of I.C. engines, 602
equivalent, 16
gas, 292
level indicator, 334
Weight, 6
Wet bulb depression, 799
temperature, 799
temperature lines, 810
Wet steam, 200
Width of impeller blades, 675
Willian’s law, 440
Winter air conditioning system, 828
Wood, 289
charcoal, 290
Wpolf type compound steam engine, 396
Work, 16.’17
ratio, 267
Workdone by air in air motor, 700
compound steam engine, 398
centrifugal air compressor, 670
during a non-flow precess, 51
for various steady flow processes, 90
single stage reciprocating air compres
sor, 639, 645
steady flow process, 89
twostage reciprocating air compressor
with intercooler, 649
Working of an ideal engine, 155
single cylinder double acting horizontal
reciprocating steam engine, 376
single stage reciprocating air compres
sor, 638
Y
Year round air conditioning, 830
Z
Zeroth law of thermodynamics, 19

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