ELEMENTS OF HEAT ENGINES

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1 ELEMENTS OF HEAT ENGINES VOLUME II (IN SI UNITS) By Late Prof. R. C. Patel B.E.TMech.) Hons., B E. (Elect.) Hons.. A.R.C.S.T. (Mech.) Hon., (Glasgow). M Sc. (Birmingham), F.I.E. (India), F.I.A.E. (India), M.I.S.T.E., M.I.F.M.. M.I.I.M. Former Vice Chancellor M.S. University of Baroda, BARODA. AND Late C. J. Karamchandani D.M.E.E. (Karachi), Senior Lecturer (Retd.). Mechanical Engineering Department. Polytechnic. M.S. University of Baroda, BARODA. Sixteenth Edition : 1997 ACHARYA PUBLICATIONS Opp. Gandhi Nagar Gruh, Vadodara

2 A ll Rights Reserved by the Authors This book or any part thereof, must not be reproduced in any form or translated without the prior written permission from the Authors. First Edition 1962 Second Edition 1966 Third Edition 1967 Fourth Edition 1968 Fifth Edition 1969 Sixth Edition 1972 Seventh Edition 1975 Eighth Edition 1977 Ninth Edition 1978 Tenth Edition 1980 Eleventh Edition 1983 Twelfth Edition 1986 Thirteenth Edition 1989 Fourteenth Edition 1992 Fifteenth Edition 1994 Sixteenth Edition 1997 Rs Published b y : Shri J. C. Shah, Proprietor - Acharya Publications, Opp. Gandhi Nagar Gruh, Vadodara Printed b y : Surendra J. Shah at Parijat Printery, 288/1, Ranip Dist. Ahmadabad, Gujarat, INDIA Typeset b y : Parijat Shah B.Com., A.C.A. * PARIJAT SHAH & ASSOCIATES, Plot No. 288/1, Ranip Dist. Ahmadabad, Gujarat, INDIA.

3 Preface to the Sixteenth Edition It is a matter of great satisfaction to the author of this book that he is required to bring out the Sixteenth Edition of this volume in such a short span of time. This by itself speaks in favour of this book in regard to its usefulness and popularity among engineering students. The author will very thankfully appreciate suggestions from readers for the improvement of the book. The author thanks Shri J. C. Shah of Acharya Publications, Vadodara and Shri Surendra J. Shah of Parijat Printery, Ahmadabad, for getting the book printed so nicely and in time. Vadodara June, 1997 C. J. Karamchandani

4 Preface to the Second Edition The second edition has been rewritten in M.KS. Units to comply with the decision of the All India Council of Technical Education for change over in the System of Units. As most of the Universities and State Technical Education Boards have switched over to M.K.S. Units, the authors feel that this edition would be quite useful both to the teachers teaching the subject and to the students. The major part of the book is overhauled to enhance the utility of the book, by making it more lucid in expression, more simplified in the subject matter and by suitable modification in the general arrangement and addition of subject matter at some places without unduly increasing the size of the book. The authors take this opportunity of thanking all those who have been good enough to draw our attention to some of the slips that had inadvertently crept in the first edition and those who offered valuable suggestions and comments with a view to make the book really one of the best of its kind. The authors will gratefully appreciate all constructive comments and suggestions from the readers. Before concluding, the authors feel it their duty to thank Sarvashri M.C. Karamchandani, B.E. (Mech.), Hon., M.M. Patel, B.E.(Mech.), K. H. Patel, B.E. (Mech.), M.C. Shah, B.E. (Mech.), B.C. Patel, D.M.E., B.C. Karamchandani, D.M.E., for checking the calculations and reading through the proofs. Our thanks are also due to Shri Karkhanis for redrawing the sketches. Our sincere thanks are also due to the publishers for getting the book published in time. Baroda 1st July, 1966 R. C. Patel C. J. Karamchandani

Preface to the First Edition This volume is intended for the use of students preparing for the final diploma examinations in Mechanical and Electrical Engineering of the Universities and State

5 Preface to the First Edition This volume is intended for the use of students preparing for the final diploma examinations in Mechanical and Electrical Engineering of the Universities and State Technical Boards. Despite the fact that several books on this subject of Heat Engines have been written and published, the long felt need of many Indian Diploma students for a Book covering completely the Heat Engines Syllabus written in a simple style has led the authors to bring out this volume in the form most suitable for Indian students preparing for the above examinations. This book which is an outcome of a very long experience of the authors in the teaching of the subject, has a special feature. Neat and simple diagrams to be found herein have gone a great way in simplifying the subject matter and have made its presentation instructive and interesting. Another useful feature of this book is a large number of examples at the end of each chapter, which are fully worked out to inspire faith and confidence in the students, who otherwise cram theory without understanding and fail to apply theory rightly and correctly in solving examples. These worked out examples may help the students not only to understand clearly the basic principles underlying them, but may also lead them to attempt without frustration the solution of examples of varied types appearing in examination papers. The practice problems added at the end of each chapter are for the benefit of students and the teachers who may use the book. The authors found it more convenient to cover the entire Heat Engines Syllabus in three volumes (Volume I, II and III). This has prevented the volume from being too bulky. Volume I is intended, for the use of students preparing for the second year diploma examinations in Mechanical and Electrical Engineering, Volume II for the final year diploma Examination in Electrical Engineering, and Volumes II and III for the final year diploma Examination in Mechanical Engineering. Utmost care has been taken in numerical calculations. They are made with the aid of slide rule, and no pains have been spared to avoid errors. And yet it is too much to be sure that all slips and errors have been detected and rectified. Authors will, therefore, very thankfully appreciate comments and suggestions from readers for the improvement of the book. The authors will feel delighted and more than compensated if the book satisfies the end in view and meets with the need of students. Before concluding, the authors feel it their duty to thank Shri M.C. Karamchandani, B.E. (Mech.) of the Polytechnic, Baroda for carefully going through the manuscript and checking it as also for solving examples. The authors also take this opportunity of expressing their thankfulness to Shri Jayantilal C.- Shah of M/s. Acharya Book Depot, Baroda for getting the volume published so nicely and in time. Baroda 1st July, 1962 R. C. Patel C. J. Karamchandani

7 CONTENTS Preface Pages Chapter 1 Steam Condensers Introduction Elements of a Steam Condensing Plant Types Jet Condensers Surface ConderSers Comparison of Jet and Surface Condensers Sources of Air in Condensers Measurement of Vacuum Estimation of Quantity of Cooling Water Dalton s Law of Partial Pressures Vacuum Efficiency Condenser Efficiency Air Pumps Cooling Water Supply 24 Tutorial-1 26 Chapter 2 Compound or Multiple Expansion Steam Engines Introduction Advantages Types Typical Terms Estimation of Cylinder Dimensions Methods of Governing 47 Tutorial-2 i 50 Chapter 3 Steam Engine And Boiler Trials * Steam Engine Trials Heat Balance Sheet Steam Boiler Trials Efficiency of Boiler Heat Balance sheet for Boiler 66 Tutorial-3 71 hapter 4 Modern Steam Generators Introduction Water Tube Boilers Materials of Construction Advantages of High Pressure Boilers Arrangement of Heating Surfaces Bokaro Plant Ramagundam Plant Chandrapura Plant Trombay Plant 85 Tutorial-4 86

8 (vii) Chapter 5 Air Standard Cycles Introduction Heat Engine Types of heat engines Available work of a cycle Efficiency of a cycle Air-Standard efficiency of a cycle Thermodynamic Reversibility Reversible cycle Ideal Heat Engine Cycle Carnot Cycle Otto Cycle or Constant Volume Cycle Diesel Cycle (Constant Pressure Cycle) Dual-Combustion Cycle Joule Cycle Mean Effective Pressure (M.E.P.) Otto Cycle Diesel Cycle Dual-Combustion Cycle Actual Cycle Thermal Efficiency 122 Tutorial Chapter 6 Internal Combustion Engines Introduction Advantages of Internal Combustion Engines over External Combustion Engines Development of I.C. Engines Classification of I.C. Engines Requirements of I.C. Engines Scavenging Methods in two-stroke Cycle Engines 131, Crossflow scavenging Full-loop or backflow scavenging Uniflow scavenging Handling of Volatile Liquid (Petrol) Fuels Simple Carburettor Zenith Carburettor Handling of Heavy Fuel Oils (Methods of Fuel Oil Injection) Fuel oil injection methods Air injection Solid injection Comparison between Solid injection and Air injection Compression-Ignition Combustion Chambers Ignition Methods Batteiy and coil ignition Compression ignition Hot-tube ignition Hot bulb ignition Ignition lag or delay period Methods of cooling I.C. Engine Cylinders Air cooling Water cooling Merits and Demerits of the Cooling Systems 144

9 (viii) 6.14 Methods of Governing I.C. Engines Hit and miss method of governing Quality method of governing Quantity method of governing Combination method of governing Highest Useful Compression Ratio Limiting compression Ratio Pre-ignition Detonation Volumetric efficiency Supercharging Thermal Efficiency of I.C. Engines 154 Tutorial Chapter 7 Testing of Internal Combustion Engines Objectives of Testing Thermodynamic Tests Measurement of Indicated power Measurement of brake power Morse test for mechanical efficiency Measurement of rate of fuel consumption and its calorific value Measurement of heat carried away by cylinder Jacket cooling water Measurement of heat carried away by the exhaust gases Heat Balance Account Performance Plotting Indicated M.E.P Indicated power Friction power Brake power Mechanical efficiency Brake M.E.P Torque Brake specific fuel consumption 177 Tutorial Chapter 8 Steam Nozzles Introduction General Forms of Nozzle Passages Steam Nozzles Flow through Steam Nozzles Velocity of leaving nozzle Mass of discharged Critical pressure ratio Areas of throat and exit for maximum discharge Length of nozzle Effect of Friction in a Nozzle Steam Injector 224 Tutorial Chapter 9 Steam Turbines Introduction Types of Steam Tur' nes Impulse Steam Turbine Velocity diagram for moving blades f:36

10 (ix) Forces on the blade and work done Effect of blade friction on velocity diagram Simple De Laval turbine Methods of reducing rotor speed or compounding of stages Velocity-compounded impulse turbines Efficiency of a velocity-compounded stage Pressure-compounded impulse turbine Reaction Steam Turbine Velocity diagram for Parsons reaction turbine Height of blades for reaction turbine Re-heat Factor Re-heating of Steam Regenerative Feed Heating or Bleeding Steam Turbine Governing Throttle governing Nozzle control govening By-pass governing Special Forms of Steam Turbines Back-pressure turbine Pass-out or extraction turbine Exhaust or low-pressure turbine Material of Construction in Steam Turbines Steam Turbines for Power Generation Other General Purpose Steam Turbines Single casing condensing type Single stage multi-stage condensing type Radial flow double rotation turbine Some Examples of Mechanical Drive Turbines 280 Tutorial Steam Tables 289

12 Steam Tables 289 STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. *C ts Specific vol. m3/kg Vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water <t>s & ' v ,

13 290 Elements of Heat Engines Vol. II STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. c ts Specific vol. m3/kg Vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water <J>w '

14 .Steam Tables 291 STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. c ts Specific vol. m3/kg vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water 4»s

15 292 Elements of Heat Engines Vol. II STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. *C ts Specific vol. m3/kg vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water <1>s ; ?

16 Steam Tables 293 STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. *C ts Specific vol. m3/kg vs water h Eothalpy kj/kg Evap.. L H Entropy kj/kg K water <&w <J>s ,

17 294 Elements of Heat Engines Vol. II STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. *C ts Specific vol. m3/kg vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water <t>w. <v ,

18 Steam Tables 295 STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. *C ts Specific vol. m3/kg vs water h Enthalpy kj/ki9 Evap. L H Entropy kj/kg K water 4>s _

19 296 Elements of Heat Engines Vol. II j STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM» (Pressure Table) Pressure bar P temp. 'C ts Specific vol. Steam m3/kg Vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water 4V <J>s > ,

20 Steam Tables 297 STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. *C ts Specific vol. m3/kg vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water <J>s

21 Elements of Heat Engines Vol. II STEAM TABLES PROPERTIES OF DRY AND SATURATED TEAM (Pressure Table) p temp. *C ts Specific vol. m3/kg vs water h Enthalpy kj/k<9 Evap. L H Entropy kj/kg K water 4>s '

22 Steam Tables 299 STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. c ts Specific vol. m3/kg vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K Sat water Qw 4>s *

23 300 Elements of Heat Engines Vol. II STEAM TABLES PROPERTIES OF DRY AND SATURATED STEAM (Pressure Table) Pressure bar P temp. c ts Specific vol. m3/kg vs water h Enthalpy kj/kg Evap. L H Entropy kj/kg K water ,

24 INDEX A Diesel ignition methods, 139 Air consumption, 175 Diesel cycle air standard efficiency, 99 Air cooling, 142 Discharge through nozzle, 202 Air ejector,, 17 Dry air pump, 16 Air injection, 135 Dual combustion cycle, 105 Air pump,, 16 E Air standard cycles, 88 Edward s air pump, 16 Air standard efficiency, 89 Efficiency, boiler, 66 Airless injection, 135, thermal, 154 Auxiliary chamber, 138, volumetric, 152 Available work of cycle, 88 Efficiency of a cycle, air standard, 89 B Ejector condenser, 2 Benson boiler, 79 Evaporative condenser, 7 Back-pressure turbine, 274 Exhaust gas calorimeter, 175 Barometric condenser, 4 - gases, heat carried away, 173 Blade velocity coefficient turbine, 275 Blade efficiency, 238 External reversibility, 90 Blade friction, 240 F Blade material, 275 Ferro concrete cooling tower, 25 Blade reduction of speed, 247 Flow of through nozzle, 202 Bleeding, , work done, 203 Boiler trials, 64 Flue gases, heat carried away, 65 Bosch fuel pump, 149 Friction power, 54 Brake power, 54 - in nozzles, 216 Brake M.E.P., in'turbine blades, 240 Brake specific fuel consumption, 177 Fuel consumption of I.C. engines, 172 Brake thermal efficiency, 155 injection methods, 135 By pass governing, 273 G C Governing of compound engine,' methods, 47 Calorific value of fuel, 64 -, cut-off. 48 Carburettor, 133 Governing of I.C. engine, methods, 145 Carnot cycle, 91 combination, 151 Cold body, 88 -, hit and miss, 146 Combustion chambers, 137 -, Quality, 147 Commercial tests, 170 -, Quantity, 150 Compound engine, cylinder dimensions, 34 Governing, throttle 54 Compound engine governing, 47 turbine, 69 Compound engine indicator diagram, 54 H Compound engine receiver type, 32 Heat balance sheet, boiler, 66 Compound engine, tandem type, 31 I.C. engine, 175 Compound engine woolfe type , engine, 55 Compounding for pressure, 254 Heat engine, 88 Compounding for velocity, pump, 90 Compression ignition, 140 High pressure cylinder, 30 Condenser efficiency, 16 Hit and miss governing, 146 Cooling pond, 25 Hot bulb ignition, 141 Cooling tower, 25 - tube ignition, 141 Cooling water supply, 24 Hot-well, 2 Convergent-divergent nozzle, 201 I Critical pressure ratio, 204 Indicator diagram, engine, 54 Cut-off governing, 48 Indicated thermal efficiency, 155 Cylinder volume ratio, 34 power, 53 D, measurement, 170 Dalton's law, 11 Indicated M.E.P., 112 De Laval turbine, 241 Ignition lag, 142 Delay period, methods, 139 Detonation, 152 Impulse turbine, 236 Diagram efficiency of turbine, 238 Intermediate cylinder, 30 Diesel cycle, 99 Ii\jector,, 224 fuel injection methods, 135 \.C. engine, delay period, 152

25 ------, governing, , heat balance sheet, , injection of fuel , supercharging, , volumetric efficiency, 152 Internal reversibility, 90 J Jet condenser, 2 Joule cycle, 109 K Kerosene oil engine, 130 L La Mont boiler, 78 Light oil engine, 130 Low pressure cylinder, 30, turbine 275 Loeffler boiler, 79 M Mean effective pressure, , Diesel, , dual, , Otto, 112 Measurement of vacuum, 8 Mechanical efficiency, 171 Modern generators, 76 Morse test, 171 Motoring test, 171 N Nozzle efficiency 217 Nozzle, 199 adiabatic flow, 202, area of throat, 206 control governing, 271 -,, length 207 maximum discharged, 204 shape of 207 supersaturate flovf, 202 throat pressure, 205 mass of discharge, Open combustion chamber, 138 Otto cycle, 93 P Parsons turbine, 255 Partial pressure, 11 Pass out turbine, 274 Pre-combustion chamber, 138 Pre-ignition, 152 Pressure compounding, 254 -velocity compounding, 247 Pyrometer, 173 Q Quality governing, 174 Quantity governing, 150 R Reaction turbine, 255 Receiver type compound engine, 32 Refrigerating machine, 90 Regenerative feed heating, 266 Reheating factor, 262 Reheating of, 263 Relative efficiency, 155 Reversible process, 90 - cycle, 90 Rotary air pump, 17 S Scavanging methods, 131 cross flow, 132 full loop, 132, uni flow, 132 Schmidt Hartmann boiler, 80 Semi-Diesel, 131 Solid injection, 136 Stage efficiency, 238 Standard eff. of cycle, Carnot, 91, Diesel, 99 Standard eff., dual, 105, Joule. 109, Otto, 93 Steam boiler trials, 64 Steam condensers, 1 Steam engine trials, 53, vacuum efficiency, 14 Steam Jackets, 56, nozzles, turbines,. 233 Supercharging, 153 Supersaturation, 202 Surface condenser, 5 T Tandem compound enginei 31 Thermal effficiency, 154 Thermodynamic reversibility, 89 - tests, 170 Throttle governing, 270 Torsional dynamometer, 54 Turbine material, 275 Turbine,, , axial discharge, 243, axial thrust, 238, blade coefficient, 241 efficiency, 238 De Laval, 241 power, 238 power generation, 276 Turbine, impulse, 236 Turbine, Parsons, 255, pressure compounding, 254 Turbine, reaction, velocity diagram, 236 Turbulence, 132 V Vacuum efficiency, 14 Velocity compounding, 247 Velocity diagram, 236 Velocity of flow, 236 of leaving nozzle, 203 of whirl, 236 Velox boiler, 81 W Water cooling, 142 Wet air pump, 16 Woolfe compound engine, 32 Z Zenith caburettor, 134

ME2301 THERMAL ENGINEERING L T P C OBJECTIVE:

ME2301 THERMAL ENGINEERING L T P C 3 1 0 4 OBJECTIVE: To integrate the concepts, laws and methodologies from the first course in thermo dynamics into analysis of cyclic processes To apply the thermodynamic