Gas turbin engineering handbook

GasTurbine Engineering Handbook Second Edition Meherwan P Boyce Managing Partner, The Boyce Consultancy Fellow, American Society of Mechanical Engineers Fellow, Institute of Diesel and Gas Turbine Engineers, u.K Gulf Professional Publishing an imprint of Butterworth-Heinemann Boston Oxford Auckland Johannesburg Melbourne New Delhi To the memory of my father, Phiroz H.J Boyce Contents Preface Preface to the First Edition Foreword to the First Edition Part I x xii xiv Design: Theory and Practice An Overview of Gas Turbines Gas Turbine Cycle in the Combined Cycle or Cogeneration Mode Gas Turbine Performance Gas Turbine Design Considerations Categories of Gas Turbines Major Gas Turbine Components Fuel Type Environmental Effects Turbine Expander Section Materials Coatings Gas Turbine Heat Recovery Supplementary Firing of Heat Recovery Systems Bibliography Theor~tical and Actual Cycle Analysis , 58 The Brayton Cycle Actual Cycle Analysis Summation of Cycle Analysis A General Overview of Combined Cycle Plants Compressed Air Energy Storage Cycle Power Augmentation Summation of the Power Augmentation Systems Bibliography 112 Compressor and Turbine Performance Characteristics Turbomachine Aerothermodynamics The Aerothermal Equations Efficiencies Dimensional Analysis Compressor Performance Characteristics Turbine Performance Characteristics Gas Turbine Performance Computation Bibliography Performance and Mechanical Standards 141 Major Variables for a Gas Turbine Application Performance Standards Mechanical Parameters Application of the Mechanical Standards to the Gas Turbine Specifications Bibliography 178 Rotor Dynamics Mathematical Analysis Application to Rotating Machines Critical Speed Calculations for Rotor Bearing Systems Electromechanical Systems and Analogies Campbell Diagram Bibliography Part II Major Components 221 Centrifugal Compressors Centrifugal Compressor Components Centrifugal Compressor Performance Compressor Surge Process Centrifugal Compressors Bibliography 275 Axial-Flow Compressors Blade and Cascade Nomenclature Elementary Airfoil Theory Laminar-Flow Airfoils Cascade Test Velocity Triangles Degree of Reaction Radial Equilibrium Diffusion Factor The Incidence Rule The Deviation Rule Compressor Stall Performance Characteristics of an Axial-Flow Compressor Stall Analysis of an Axial-Flow Compressor Bibliography 319 Radial-Inflow Turbines Description Theory Turbine Design Considerations Losses in a Radial-Inflow Turbine Performance of a Radial-Inflow Turbine Bibliography vii viii Contents 337 Axial-Flow Turbines Turbine Geometry Impulse Turbine The Reaction Turbine Turbine Blade Cooling Concepts Turbine Blade Cooling Design Cooled-Turbine Aerodynamics Turbine Losses Bibliography 370 10 Combustors Combustion Terms Combustion Combustion Chamber Design Fuel Atomization and Ignition Typical Combustor Arrangements Air Pollution Problems Catalytic Combustion Bibliography Part III Materials, Fuel Technology, and Fuel Systems 411 11 Materials General Metallurgical Behaviors in Gas Turbines Gas Turbine Materials Compressor Blades Forgings and Nondestructive Testing Coatings Bibliography 436 12 Fuels Fuel Specifications Fuel Properties Fuel Treatment Heavy Fuels Cleaning of Turbine Components Fuel Economics Operating Experience Heat Tracing of Piping Systems Types of Heat-Tracing Systems Storage of Liquids Bibliography Part IV Auxiliary Components and Accessories 469 13 Bearings and Seals Bearings Bearing Design Principles Tilting-Pad Journal Bearings Bearing Materials Bearing and Shaft Instabilities Thrust Bearings Factors Affecting Thrust-Bearing Design ThrustBearing Power Loss Seals Noncontacting Seals Mechanical (Face) Seals Mechanical Seal Selection and Application Seal Systems Associated Oil System Dry Gas Seals Bibliography 521 14 Gears Gear Types Factors Affecting Gear Design Manufacturing Processes Installation and Initial Operation Bibliography Part V Installation, Operation, and Maintenance 541 15 Lubrication Basic Oil System Lubricant Selection Oil Sampling and Testing Oil Contamination Filter Selection Cleaning and Flushing Coupling Lubrication Lubrication Management Program Bibliography 558 16 Spectrum Analysis Vibration Measurement Taping Data Interpretation of Vibration Spectra Subsynchronous Vibration Analysis Using RTA Synchronous and Harmonic Spectra Bibliography 584 17 Balancing Rotor Imbalance Balancing Procedures Application of Balancing Techniques User's Guide for Multiplane Balancing Bibliography 605 18 Couplings and Alignment Gear Couplings Metal Diaphragm Couplings Metal Disc Couplings Turbomachinery Uprates Shaft Alignment Bibliography Contents ix 19 Control Systems and Instrumentation 634 Control Systems Condition Monitoring Systems Monitoring Software Implementation of a Condition Monitoring System Life Cycle Costs Temperature Measurement Pressure Measurement Vibration Measurement Auxiliary System Monitoring The Gas Turbine Failure Diagnostics Mechanical Problem Diagnostics Summary Bibliography 20 Gas Turbine Performance Test 692 Introduction Performance Codes Flow Straighteners Gas Turbine Test Gas Turbine Performance Curves Performance Computations Gas Turbine Performance Calculations Plant Losses Bibliography 21 Maintenance Techniques 722 Philosophy of Maintenance Training of Personnel Tools and Shop Equipment Turbomachinery Cleaning Hot-Section Maintenance Compressor Maintenance Bearing Maintenance Coupling Maintenance Rejuvenation of Used Turbine Blades Repair and Rehabilitation of Turbomachinery Foundations Large Machinery Startup Procedure Typical Problems Encountered in Gas Turbines Bibliography Appendix: Equivalent Units Index About the Author , , , , , , 778 782 799 Preface Gas Turbine Engineering Handbook discusses the design, fabrication, installation, operation, and maintenance of gas turbines The second edition is not only an updating of the technology in gas turbines, which has seen a great leap forward in the 1990s, but also a rewriting of various sections to better answer today's problems in the design, fabrication, installation, operation, and maintenance of gas turbines The new advanced gas turbines have firing temperatures of 2600OF (1427°q, and pressure ratio's exceeding 40:1 in aircraft gas turbines, and over 30:1 in industrial turbines Advances in materials, and coatings have spurred this technology, and the new edition has treated this new area in great detail The emphasis on low NOx emissions from gas turbines has led to the development of a new breed of dry low NOx combustors, which are dealt in depth in this new edition The second edition deals with an upgrade of most of the applicable codes both in the area of performance and mechanical standards The book has been written to provide an overall view for the experienced engineer working in a specialized aspect of the subject and for the young engineering graduate or undergraduate student who is being exposed to the turbo machinery field for the first time The book will be very useful as a textbook for undergraduate turbomachinery courses as well as for in-house company training programs related to the petrochemical, power generation, and offshore industries The use of gas turbines in the petrochemical, power generation, and offshore industries has mushroomed in the past few years In the past 10 years, the power industry has embraced the Combined Cycle Power Plants and the new high efficiency gas turbines are at the center of this growth segment of the industry This has also led to the rewriting of chapters and It is to these users and manufacturers of gas turbines that this book is directed The book will give the manufacturer a glimpse of some of the problems associated with his equipment in the field and help the user to achieve maximum performance efficiency and high availability of his gas turbines I have been involved in the research, design, operation, and maintenance of gas turbines since the early 1960s I have also taught courses at the graduate and undergraduate level at the University of Oklahoma and Texas A&M University, and now, in general, to the industry There have been over 3,000 students through my courses designed for the engineer in the field representing over 400 companies from around the world Companies have x Preface xi used the book, and their comments have been very influential in the updating of material in the second edition The enthusiasm of the students associated with these courses gave me the inspiration to undertake this endeavor The many courses I have taught over the past 25 years have been an educational experience for me as well as for the students The Texas A&M University Turbomachinery Symposium, which I had the privilege to organize and chair for over eight years and be part of the Advisory Committee for 30 years, is a great contributor to the operational and maintenance sections of this book The discussions and consultations that resulted from my association with highly professional individuals have been a major contribution to both my personal and professional life as well as to this book In this book, I have tried to assimilate the subject matter of various papers (and sometimes diverse views) into a comprehensive, unified treatment of gas turbines Many illustrations, curves, and tables are employed to broaden the understanding of the descriptive text Mathematical treatments are deliberately held to a minimum so that the reader can identify and resolve any problems before he is ready to execute a specific design In addition, the references direct the reader to sources of information that will help him to investigate and solve his specific problems It is hoped that this book will serve as a reference text after it has accomplished its primary objective of introducing the reader to the broad subject of gas turbines I wish to thank the many engineers whose published work and discussions have been a cornerstone to this work I especially thank all my graduate students and former colleagues on the faculty of Texas A&M University without whose encouragement and help this book would not be possible Special thanks go to the Advisory Committee of the Texas A&M University Turbomachinery Symposium and Dr M Simmang, Chairman of the Texas A&M University Department of Mechanical Engineering, who were instrumental in the initiation of the manuscript I wish to acknowledge and give special thanks to my wife, Zarine, for her readiness to help and her constant encouragement throughout this project I sincerely hope that this new edition will be as interesting to read as it was for me to write and that it will be a useful reference to the fast-growing field of turbomachinery Finally, I would like to add that the loss of my friend and mentor Dr C.M Simmang who has written the foreword to the first edition of this book is a deep loss not only to me but also to the engineering educational community and to many of his students from Texas A&M University Meherwan P Boyce Houston, Texas Preface to the First Edition Gas Turbine Engineering Handbook discusses the design, fabrication, installation, operation, and maintenance of gas turbines The book has been written to provide an overall view for the experienced engineer working in a specialized aspect of the subject and for the young engineering graduate or undergraduate student who is being exposed to the turbomachinery field for the first time The book will be very useful as a textbook for undergraduate turbo machinery courses as well as for in-house company training programs related to the petrochemical, power generation, and offshore industries The use of gas turbines in the petrochemical, power generation, and offshore industries has mushroomed in the past few years It is to these users and manufacturers of gas turbines that this book is directed The book will give the manufacturer a glimpse of some of the problems associated with his equipment in the field and help the user to achieve maximum performance efficiency and high availability of his gas turbines I have been involved in the research, design, operation, and maintenance of gas turbines since the early 1960s I have also taught courses at the graduate and undergraduate level at the University of Oklahoma and Texas A&M University, and now, in general, to the industry The enthusiasm of the students associated with these courses gave me the inspiration to undertake this endeavor The many courses I have taught over the past 15 years have been an educational experience for me as well as for the students The Texas A&M University Turbomachinery Symposium, which I had the privilege to organize and chair for seven years, is a great contributor to the operational and maintenance sections of this book The discussions and consultations that resulted from my association with highly professional individuals have been a major contribution to both my personal and professionallife as well as to this book In this book, I have tried to assimilate the subject matter of various papers (and sometimes diverse views) into a comprehensive, unified treatment of gas turbines Many illustrations, curves, and tables are employed to broaden the understanding of the descriptive text Mathematical treatments are deliberately held to a minimum so that the reader can identify and resolve any problems before he is ready to execute a specific design In addition, the references direct the reader to sources of information that will help him to investigate and solve his specific problems It is hoped that this book will xii Preface to the First Edition xiii serve as a reference text after it has accomplished its primary objective of introducing the reader to the broad subject of gas turbines I wish to thank the many engineers whose published work and discussions have been a cornerstone to this work I especially thank all my graduate students and former colleagues on the faculty of Texas A&M University without whose encouragement and help this book would not be possible Special thanks go to the Advisory Committee of the Texas A&M University Turbomachinery Symposium and Dr CM Simmang, Chairman of the Texas A&M University Department of Mechanical Engineering, who were instrumental in the initiation of the manuscript, and to Janet Broussard for the initial typing of the manuscript Acknowledgment is also gratefully made of the competent guidance of William Lowe and Scott Becken of Gulf Publishing Company Their cooperation and patience facilitated the conversion of the raw manuscript to the finished book Lastly, I wish to acknowledge and give special thanks to my wife, Zarine, for her readiness to help and her constant encouragement throughout this project I sincerely hope that this book will be as interesting to read as it was for me to write and that it will be a useful reference to the fast-growing field of turbomachinery M eherwan P Boyce Houston, Texas 278 Gas Turbine Engineering Handbook The airfoils are curved, convex on one side and concave on th.~other, with the rotor rotating toward the concave side The concave side is called the pressure side of the blade, and the convex side is called the suction side of the blade The chordline of an airfoil is a straight line drawn from the leading edge to the trailing edge of the airfoil, and the chord is the length of the chordline (See Figure 7-4.) The camberline is a line drawn halfway between the two surfaces, and the distance between the camberline and the chordline is the camber of the blade The camber angle () is the turning angle of the camber line The blade shape is described by specifying the ratio of the chord to the camber at some particular length on the chordline, measured from the leading edge The aspect ratio AR is the ratio of the blade length to the chord length The term "hub-to-tip ratio" is frequently used instead of aspect ratio The aspect ratio becomes important when three-dimensional flow characteristics are discussed The aspect ratio is established when the mass flow and axial velocity have been determined Axial-FlowCompressors 279 The pitch Sb of a cascade is the distance between blades, usually measured between the camberlines at the leading or trailing edges of the blades The ratio of the chord length to the pitch is the solidity a of the cascade The solidity measures the relative interference effects of one blade with another If the solidity is on the order of 0.5-0.7, the single or isolated airfoil test data, from which there are a profusion of shapes to choose, can be applied with considerable accuracy The same methods can be applied up to a solidity of about 1.0 but with reduced accuracy When the solidity is on the order of 1.0-1.5, cascade data are necessary For solidity in excess of 1.5, the channel theory can be employed The majority of present designs are in the cascade regIOn The blade inlet angle (3] is the angle formed by a line drawn tangent to the forward end of the camber line and the axis of the compressor The blade outlet angle (32 is the angle of a line drawn tangent to the rear of the camberline Subtracting (32from (3] gives the blade camber angle The angle that the chordline makes with the axis of the compressor is "(, the setting or stagger angle of the blade High-aspect ratio blades are often pretwisted so that at full operational speed the centrifugal forces acting on the blades will untwist the blades to the designed aerodynamic angle The pretwist angle at the tip for blades with AR ratios of about four is between two and four degrees The air inlet angle a], the angle at which incoming air approaches the blade, is different from (3] The difference between these two angles is the incidence angle i The angle of attack a is the angle between the inlet air direction and the blade chord As the air is turned by the blade, it offers resistance to turning and leaves the blade at an angle greater than (32 The angle at which the air does leave the blade is the air outlet angle a2 The difference between (32 and a2 is the deviation angle The air turning angle is the difference between a] and a2 and is sometimes called the deflection angle The original work by NACA and NASA is the basis on which most modern axial-flow compressors are designed Under NACA, a large number of blade profiles were tested The test data on these blade profiles is published The cascade data conducted by NACA is the most extensive work of its kind In most commercial axial-flow compressors NACA 65 series blades are used These blades are usually specified by notation similar to the following: 65-(18) 10 This notation means that the blade has a lift coefficient of 1.8, a profile shape 65, and a thickness/chord ratio of 10% The lift coefficient can be directly related to the blade camber angle by the following relationship for 65 series blades: (7 -1 ) 280 Gas Turbine Engineering Handbook Elementary Airfoil Theory When a single airfoil is parallel to the velocity of a flowing gas, the air flows over the airfoil as shown in Figure 7-5a The air divides around the body, separates at the leading edge, and joins again at the trailing edge of the body The main stream itself suffers no permanent deflection from the presence of the airfoil Forces are applied to the foil by the local distribution of the stream and the friction of the fluid on the surface If the airfoil is well designed, the flow is streamlined with little or no turbulence If the airfoil is set at the angle of attack to the air stream (as in Figure 7-5b), a greater disturbance is created by its presence, and the streamline pattern will change The air undergoes a local deflection, though at some distance ahead of and behind the body the flow is still parallel and uniform The upstream disturbance is minor compared to the downstream disturbance The local deflection of the air stream can, by Newton's laws, be created only if the blade exerts a force on the air; thus, the reaction of the air must produce an equal and opposite force on the airfoil These forces can appear only in the form of a pressure stream on the airfoil The presence of Axial-Flow Compressors 281 the airfoil has changed the local pressure distribution and, by the Bernoulli equation, the local velocities Examination of the streamlines about the body shows that over the top of the airfoil, the lines approach each other, indicating an increase of velocity and a reduction in static pressure On the underside of the airfoil, the action separates the streamlines, resulting in a static pressure increase Measurement of the pressure at various points on the surface of the airfoil will reveal a pressure distribution as shown in Figure 7-5c The vectorial sum of these pressures will produce some resultant force acting on the blade This resultant force can be resolved into a lift component L at right angles to the undisturbed air stream, and a drag component D, moving the airfoil in the direction of flow motion This resultant force is assumed to act through a definite point located in the airfoil so that the behavior will be the same as if all the individual components were acting simultaneously By experimentation, it is possible to measure the lift and drag forces for all values of airflow velocity, angles of incidence, various airfoil shapes Thus, for anyone airfoil the acting forces can be represented as shown in Figure 7-6a Using such observed values, it is possible to define relations between the forces (7-2) (7-3) where: L = lift force D = drag force CL = lift coefficient = drag coefficient A = surface area CD p = fluid density V = fluid velocity Two coefficients have been defined, CL and CD, relating velocity, density, area, and lift or drag forces These coefficients can be calculated from windtunnel tests and plotted as shown in Figure 7-6b versus the angle of attack 282 Gas Turbine Engineering Handbook for any desired section These curves can then be employed in all future predictions involving this particular foil shape Examination of Figure 7-6b reveals that there is an angle of attack that produces the highest lift force and lift coefficient If this angle is exceeded, the airfoil "stalls" and the drag force increases rapidly As this maximum angle is approached, a great percentage of the energy available is lost in overcoming friction, and a reduction in efficiency occurs Thus, there is a point, usually before the maximum lift coefficient is reached, at which the most economical operation occurs as measured by effective lift for a given energy supply Axial-FlowCompressors 283 Laminar-Flow Airfoils Just before and during World War II, much attention was given to laminar-flow airfoils These airfoils are designed so that the lowest pressure on the surface occurs as far back as possible The reason for this design is that the stability of the laminar boundary layer increases when the external flow is accelerated (in the flow with a pressure drop), and the stability decreases when the flow is directed against increasing pressure A considerable reduction in skin friction is obtained by extending the laminar region in this way, provided that the surface is sufficiently smooth A disadvantage of this type of airfoil is that the transition from laminar to turbulent flow moves forward suddenly at small angles of attack This sudden movement results in a narrow low-drag bucket, which means that the drag at moderate-to-Iarge attack angles is much greater than an ordinary airfoil for the same attack angle as seen in Figure 7-7 This phenomenon can be attributed to the minimum pressure point moving forward; therefore, the point of transition between laminar and turbulent flow is also advanced toward the nose as shown in Figure 7-8 The more an airfoil is surrounded by turbulent airflow, the greater its skin friction 284 Gas Turbine Engineering Handbook Cascade Test The data on blades in an axial-flow compressor are from various types of cascades, since theoretical solutions are very complex, and their accuracy is in question because of the many assumptions required to solve the equations The most thorough and systematic cascade testing has been conducted by NACA staff at the Lewis Research Center The bulk of the cascade testing was carried out at low mach numbers and at low turbulence levels The NACA 65 blade profiles were tested in a systematic manner by Herrig, Emery, and Erwin The cascade tests were carried out in a cascade wind tunnel with boundary-layer suction at the end walls Tip effects were studied in a specially designed water cascade tunnel with relative motion between wall and blades Cascade tests are useful in determining all aspects of secondary flow For better visualization, tests have been conducted in water cascades The flow patterns are studied by injecting globules of dibutyl phatalate and kerosene in a mixture equal to the density of water The mixture is useful in tracing secondary flow, since it does not coagulate An impeller designed for air can be tested using water if the dimensionless parameters, Reynolds number, and specific speed are held constant (7-4) (7-5) Axial-FlowCompressors 285 where: Using this assumption, one can apply this flow visualization method to any working medium One designed apparatus consists of two large tanks on two different levels The lower tank is constructed entirely out of plexiglass and receives a constant flow from the upper tank The flow entering the lower tank comes through a large, rectangular opening, which houses a number of screens so that no turbulence is created by water entering the lower tank The center of the lower tank can be fitted with various boxes for the various flow visualization problems to be studied This modular design enables a rapid interchanging of models and work on more than one concept at a time To study the effect of laminar flow, the blades were slotted as shown in Figure 7-9 For the blade treatment cascade rig experiment, a plexiglass cascade was designed and built Figure 7-10 shows the cascade This cascade 286 Gas Turbine Engineering Handbook was then placed in the bottom tank and maintained at a constant head Figure 7-11 shows the entire setup, and Figure 7-12 shows the cascade flow Note the large extent of the laminar-flow regions on the treated center blades as compared to the untreated blades The same water tunnel was used for tests to study the effect of casing treatment in axial-flow compressors In this study, the same Reynolds number and specific speeds were maintained as those experienced in an actual axialflow compressor In an actual compressor the blade and the passage are rotating with respect to the stationary shroud It would be difficult for a stationary observer to obtain data on the rotating blade passage However, if that observer were rotating with the blade passage, data would be easier to acquire This was accomplished by holding the blade passage stationary with respect to the observer and rotating the shroud Furthermore, since casing treatment affects the region around the blade tip, it was sufficient to study only the upper portion of the blade passage These were the criteria in the design of the apparatus The modeling of the blade passage required provisions for controlling the flow in and out of the passage This control was accomplished by placing the blades, which partially form the blade passage, within a plexiglass tube The tube had to be of sufficient diameter to accommodate the required flow through the passage without tube wall effect distorting the flow as it entered or left the blade passage This allowance was accomplished by using a tube three times the diameter of the blade pitch The entrance to the blades was designed so that the flow entering the blades was a fully developed turbulent flow The flow in the passage between the blade tip and the rotating shroud was laminar This laminar flow was expected in the narrow passage A number of blade shapes could have been chosen; therefore, it was necessary to pick one shape for this study which would be the most representative for casing treatment considerations Since casing treatment is most effective from an acoustic standpoint in the initial stages of compression, the maximum point of camber was chosen toward the rear of the blade (Z = chord) This type of blade profile is most commonly used for transonic flow and is usually in the initial stages of compression The rotating shroud must be in close proximity to the blade tips within the tube To get this proximity, a shaft-mounted plexiglass disc was suspended from above the blades The plexiglass disc was machined as shown in Figure 7-13 The plexiglass tube was slotted so that the disc could be centered on the center line of the tube and its stepped seclion lowered through the two slots in the tube Clearances between the slot edges and the disc were minimized 288 Gas Turbine Engineering Handbook One slot was cut directly above the blade passage emplacement The other slot was sealed off to prevent leakage As the disc was lowered into close proximity to the blade tips, the blade passage was completed The clearance between disc and blade was kept at 0.035 of an inch The disc, when spun from above, acted as the rotating shroud There are only two basic casing treatment designs other than a blank design-which corresponds to no casing treatment at all The first type of casing treatment consists of radial grooves A radial groove is a casing treatment design in which the groove is essentially parallel to the chordline of the blade The second basic type is the circumferential groove This type of casing treatment has its grooves perpendicular to the blade chordline Figure 7-14 is a photograph of two discs showing the two types of casing Axial-FlowCompressors 289 treatment used The third disc used is a blank, representing the present type of casing The results indicate that the radial casing treatment is most effective in reducing leakage and also in increasing the surge-to-stall margin Figure 7-15 shows the leakage at the tips for the various casing treatments Figure 7-16 shows the velocity patterns observed by the use of various casing treatments Note that for the treatment along the chord (radial), the flow is maximum at the tip This flow maximum at the tip indicates that the chance of rotor tip stall is greatly reduced Energy Increases In an axial flow compressor air passes from one stage to the next with each stage raising the pressure and temperature slightly By producing lowpressure increases on the order of 1.1: 1-1.4: 1, very high efficiencies can be obtained The use of multiple stages permits overall pressure increases up to 290 Gas Turbine Engineering Handbook Axial-Flow Compressors 291 40:1 Figure 7-3 shows the pressure, velocity, and total enthalpy variation for flow through several stages of an axial flow compressor It is important to note here that the changes in the total conditions for pressure, temperature, and enthalpy occur only in the rotating component where energy is inputted into the system As seen also in Figure 7-3, the length of the blades, and the annulus area, which is the area between the shaft and shroud, decreases through the length of the compressor This reduction in flow area compensates for the increase in fluid density as it is compressed, permitting a constant axial velocity In most preliminary calculations used in the design of a compressor, the average blade height is used as the blade height for the stage The rule of thumb for a multiple stage gas turbine compressor would be that the energy rise per stage would be constant, rather than the commonly ... Overview of Gas Turbines Gas Turbine Cycle in the Combined Cycle or Cogeneration Mode Gas Turbine Performance Gas Turbine Design Considerations Categories of Gas Turbines Major Gas Turbine Components... times of the year 16 Gas Turbine Engineering Handbook Categories of Gas Turbines The simple cycle gas turbine is classified into five broad groups: Frame Type Heavy-Duty Gas Turbines The frame... Aircraft-Derivative Gas Turbines Aeroderivative gas turbines consist of two basic components: an aircraftderivative gas generator, and a free-power turbine The gas generator serves as a producer of gas energy