PROPULSIONTHE RANDOM HOUSE COLLEGE

PROPULSION
THE RANDOM HOUSE COLLEGE DICTIONARY defines propulsion as “the act of propelling, the state of being propelled, a propelling force or impluse” and defines the verb PROPEL as “to drive, or cause to move, forward or onward”. From these definitions, we can conclude that the study of propulsion includes the study of the propelling force, the motion caused, and the bodies involved. Propulsion involves an object to be propelled plus one or more additional bodies, called propellant.
The study of propulsion is concerned with venicles such as automobiles, train, ships, aircraft, and spacecraft. The focus of this textbook is on the propulsion of aircraft and spacecraft. Methods devised to produce a thrust force for the propulsion of a vehicle in flight are based on the principle of jet propulsion (the momentum changevof a fluid by the propulsion system). The fluid may be the gas used by engine it self (turbojet) it may be a fluid available in the surrounding environment (air used by a propeller). Or it may be stored in the vehicle and carried by it during the flight (rocket)
Jet propulsion system can be subdivided into two broad categories air-breathing and non-breating. Air-breating propulsion system include the reciprocating, turbojet, turbofan, ramjet, turboprop, and turboshaft engine. Non air breating engines include rocket motors, nuclear propulsion system, and electric propulsion system. We focus on gas turbine propulsion system (turbojet, turbofan, turboprop, and turboshaft engine) in this textbook.
The material in this textbook is divided into three parts :
• Basic concepts and one-dimensional gas dynamics
• Analysis and performance of air-breathing propultion system
• Analysis of gas turbine engine components

This chapter introduces the type of air-breathing and rocket propulsion system and the basic propultion performance parmeters. Also included is an introduction to aircraft and rocket performance. The material on aircraft performance shows the influence of the gas turbin engine performance on the performance of the aircraft system. This material also permits incorporation of agas turbine engine design problem such as new engine for an existing aircraft.
Numerous examples are included throughout this book to help student see the aplication of a concept after it is introdused. For some students, the material on basic concepts and gas dynamics will be a review of material covered in other courses they have already taken. For other students, this may be their first exposure to this material, and it may require more effort to understand.


UNIT AND DIMENSIONS

Since the engineering world uses both the metric SI and english unit system, both will be used in this textbook. One singular distinction exists between the english system and SI the unit of force is defined in the former but derived un the latter. Newton’s law of motion relates force to mass, lenght, and time. It states that the sum of the forces is proportional to the rate of change of the momentum (M = m V) the constant of proportionality is 1/g.
The unit for each term in the above equation are listed in table 1-1 for both SI and english units. In any unit system, only four of the five items in the table can be specified, and the latter is derived from eq (1-1)
As a result of selecting g=1 and defining the units off mass, lenght and time in SI units, the unit of force is derived from eq. (1-1) as kilogram-meters per square second (kg.m/sec2), which is called the newton (N). In english units, the value of gc is derived from eq (1-1) as
Rather than adopt the convention used in many recent textbook of developing material or use with only SI metric units (gc=1). We will maintain gc in all our equations. Thus gc will also show up in the equation for potential energy (PE) and kinetic energy (KE):
The total energy per unit mass e is the sum of the specific internal energy u, specific kinetic ke, and specific potential energy pe
There are multitude of engineenring unit for the quantities of interest in propulsion. For example, energy can be expressed in the SI unit of joule (1j=1n.m), in british thermal units (btu’s), or in foot-pound force (ft.lbf). one must be able to use the available 1-2 is a unit conversion table provided to help you in your endeavors.


OPERATIONAL ENVELOPES AND STANDARD ATMOSPHERE

Each engine type will operate only within a certain range of altitudes and mach number (velocities). Similar limitaions in velocity and altitude exixt for airframe. It is necessary, therefore, to match airframe and propulsion system capabilities. Figure 1-1 shows the approximate velocity and altitude limits, or CORIDOR OF FLIGHT, within which airlift vehicles can operate. The corridor is bounded by a lift limit, a temperature limit, and an aerodynamic force limit. The lift limit determined by the maximum level-flight altitude at a given velocity. the temperature limit is set by the structural thermal limit of the material used in construction of the aircraft. At any given altitude, the maximum velocity attained is temperature-limited by aerodynamic heating effect. At lower altitude, velocity is limited by aerodynamic force loads rather than by temperature
The operating regions of all aircraft lie within the flight corridor. The operating region of a particular aircraft within the corridor is determined by aircraft design, but it is very a very small portion of the overall corridor. Superimposed on the flight corridor in FIG 1-1 are the operational envelopes of various powered aircraft. The operational limits of each propulsion system are determined by limitations of the components of the propulsion system and are shown in FIG 1-2.
The analyses presented in this text use the properties of the atmosphere to determine both engine and airframe performance. Since these properties vary with location, season, time of the day, etc. We will use the U.S standard



atmosphere (Ref. 2) to give a known foundationl for our analyses. Appendix A

gives the properties of the U.S. standrd atmosphere, 1976, in both English

and SI units. Values of the pressure P, temperature T, density p, and speed of

sound a are given in dimensionless ratios of the property at altitude to its

value at sea level (SL), (the reference value). The dimensionless ratios of

pressure, temperature, and density are given the symbols O, and u,












The reference values of pressure, temperature, and density are given for each

unit system at the end of its property table.

For nonstandard conditions such as a hot day, the normal procedure is to

use the standard pressure and correct the density. using the perfect gas

relationship o = 6/6. As an example, we consider a 100°F day at 4-kft altitude.

From App. A, we have 8 = 0.8637 for the 4-kft altitude. We calculate 0, using

the 100°F temperature; O = T/T= (100 + 459.7)/518.7 = 1.079. Note that

absolute temperatures must be used in calculating 0. Then the density ratio is

calculated using o 6/8 = 0.8637/1.079 = 0.8005.

1-4 AIR-BREATHING ENGINES

The turbojet, turbofan, turboprop, turboshaft, and ramjet engine systems are

discussed in this part of Chap. 1. The discussion of these engines is in the

context of providing thrust for aircraft. The listed engines are not all the

engine types (reciprocating, rockets, combination types, etc.) that are used in

providing propulsive thrust to aircraft, nor are they used exclusively on

aircraft. The thrust of the turbojet and ramjet results from the action of a fluid

jet leaving the engine; hence, the name jet engine is often applied to these

engines. The turbofan, turboprop, and turboshaft engines are adaptations of

the turbojet to supply thrust or power through the use of fans, propellers, and

shafts.

Gas Generator

The “heart” of a gas turbine type of engine is the gas generator. A schematic

diagram of a gas generator is shown in Fig. 1-3. The compressor, combustor,

and turbine are the major components of the gas generator which is common

to the turbojet, turbofan, turboprop, and turboshaft engines. The purpose of a

gas generator. is to supply high-temperature and high-pressure gas.






TUJUHHHH
The Turbojet

By adding an inlet and a nozzle to the gas generator, a turbojet angine can he

constructed. A schematic diagram of a simpte turbojet is shown in Fig. 1-4ò.

and a turbojet with afterburner is shown in Fig. 1-45. In the analysis of a

turbojet engine, the major components are treated as sections. Also shown in

Figs. 1-4a and 1-4b are the station numbers for each section


DELAPANNN
Schematic diagram of a turbojet With afterburner.

The.turbojet was first used as a means of aircraft propulsion..by

chain (first flight August 27, 1939) and Whittle (first flight May 15, 1941). As

development proceeded, the turbojet engine became more efficient and

replaced some of the piston engines. A photograph of the J79 turbojet with

afterburner used in the F-4 Phantom II and B-58 Hustler is shown in Fig. 1-5.




SEMBILANNN
The adaptations of the turbojet in the form of turbofan, turboprop, and

turboshaft engines came with the need for more thrust at relatively low speeds.

Some characteristics of different turbojet, turbofan, turboprop, and turboshaft

engines are included in App. B.

The thrust of a turbojet is developed by compressing air in the inlet and

compressor, mixing the air with fuel and burning in the combustor, and

expanding the gas stream through the turbine and nozzle. The expansion of

gas through the turbine supplies the power to turn the compressor. The net

thrust delivered by the engine is the result of converting internal energy to

kinetic energy.

The pressure, temperature, and velocity variations through a J79 engine

are shown in Fig. 1-6. in the compressor section, the pressure and temperature

increase as a result of work being done on the air. The temperature of the gas

is further increased by burning in the combustor.

Hasil (Bahasa Indonesia) 1:

PROPULSIRANDOM HOUSE COLLEGE DICTIONARY mendefinisikan propulsi sebagai "tindakan pasir, keadaan menjadi didorong, kekuatan yang mendorong atau impluse" dan mendefinisikan kata PROPEL sebagai "untuk drive, atau menyebabkan untuk bergerak, maju atau seterusnya". Dari definisi ini, kita dapat menyimpulkan bahwa studi propulsi mencakup studi Angkatan mendorong, gerakan disebabkan dan badan-badan yang terlibat. Propulsi melibatkan objek untuk didorong ditambah satu atau lebih badan tambahan, disebut propelan.Studi propulsi berkaitan dengan venicles seperti mobil, kereta, kapal, pesawat, dan pesawat ruang angkasa. Fokus dari buku ini adalah Propulsi pesawat dan pesawat ruang angkasa. Metode yang dirancang untuk menghasilkan gaya dorong untuk propulsi kendaraan dalam penerbangan didasarkan pada prinsip dari jet (cairan oleh sistem propulsi changevof momentum). Cairan mungkin gas digunakan oleh mesin pencari itu sendiri (turbojet) mungkin cairan tersedia di lingkungan sekitar (udara digunakan oleh baling-baling). Atau mungkin disimpan di dalam kendaraan dan terbawa selama penerbangan (roket)Jet propulsion sistem dapat dibagi menjadi dua kategori luas udara untuk bernafas dan bebas-breating. Sistem propulsi udara-breating termasuk mesin turbojet, turbofan, ramjet, turboprop, dan turboshaft reciprocating. Udara bebas breating mesin termasuk motor roket, sistem propulsi nuklir dan sistem propulsi listrik. Kami fokus pada sistem propulsi turbin gas (mesin turbofan, turbojet, turboprop dan turboshaft) dalam buku ini.The material in this textbook is divided into three parts :• Basic concepts and one-dimensional gas dynamics• Analysis and performance of air-breathing propultion system• Analysis of gas turbine engine componentsThis chapter introduces the type of air-breathing and rocket propulsion system and the basic propultion performance parmeters. Also included is an introduction to aircraft and rocket performance. The material on aircraft performance shows the influence of the gas turbin engine performance on the performance of the aircraft system. This material also permits incorporation of agas turbine engine design problem such as new engine for an existing aircraft.Numerous examples are included throughout this book to help student see the aplication of a concept after it is introdused. For some students, the material on basic concepts and gas dynamics will be a review of material covered in other courses they have already taken. For other students, this may be their first exposure to this material, and it may require more effort to understand.UNIT AND DIMENSIONSSince the engineering world uses both the metric SI and english unit system, both will be used in this textbook. One singular distinction exists between the english system and SI the unit of force is defined in the former but derived un the latter. Newton’s law of motion relates force to mass, lenght, and time. It states that the sum of the forces is proportional to the rate of change of the momentum (M = m V) the constant of proportionality is 1/g.Unit untuk setiap istilah dalam persamaan di atas tercantum dalam tabel 1-1 untuk SI dan satuan Inggris. Dalam setiap unit sistem, hanya empat dari lima item dalam tabel dapat ditentukan, dan yang kedua berasal dari eq (1-1)Sebagai akibat dari memilih g = 1 dan mendefinisikan unit dari massa, panjang dan waktu di unit SI, unit Angkatan berasal dari EQ (1-1) sebagai kilogram-meters per detik persegi (kg.m/sec2), yang disebut newton (N). Dalam satuan Inggris, nilai gc berasal dari eq (1-1) sebagaiDaripada mengadopsi Konvensi digunakan dalam banyak buku hari mengembangkan bahan atau menggunakan dengan hanya SI unit metrik (gc = 1). Kami akan menjaga gc di semua persamaan kami. Dengan demikian gc akan juga muncul dalam persamaan untuk energi potensial (PE) dan energi kinetik (KE):Total energi per unit massa e adalah jumlah tertentu energi internal u, tertentu ke kinetik, dan energi potensial yang spesifik peAda banyak engineenring unit untuk jumlah kepentingan dalam propulsi. Sebagai contoh, energi dapat dinyatakan dalam satuan SI joule (1j=1n.m), unit termal Inggris (btu), atau kekuatan foot-pound (ft.lbf). salah satu harus dapat menggunakan yang tersedia 1-2 adalah tabel konversi unit yang tersedia untuk membantu Anda dalam usaha Anda.AMPLOP OPERASIONAL DAN SUASANA STANDARMasing-masing jenis mesin akan beroperasi hanya dalam berbagai ketinggian dan mach jumlah (kecepatan). Limitaions serupa di kecepatan dan ketinggian exixt untuk airframe. Hal ini diperlukan, oleh karena itu, untuk mencocokkan kemampuan sistem airframe dan propulsi. Gambar 1-1 menunjukkan perkiraan kecepatan dan ketinggian batas, atau CORIDOR penerbangan, di mana kendaraan pengangkutan melalui udara dapat beroperasi. Koridor dibatasi oleh batas angkat, suhu batas, dan batas aerodinamis kekuatan. Angkat batas ditentukan oleh tingkat penerbangan ketinggian maksimum pada kecepatan tertentu. batas suhu diatur secara struktural batas termal bahan yang digunakan dalam konstruksi pesawat. Pada setiap ketinggian tertentu, kecepatan maksimum mencapai suhu-terbatas oleh efek aerodinamis Penghangat Ruangan. Di ketinggian rendah, kecepatan dibatasi oleh kekuatan aerodinamis beban bukan oleh suhu Daerah operasi semua pesawat terletak dalam koridor penerbangan. Wilayah operasi pesawat tertentu dalam koridor ditentukan oleh desain pesawat, tapi itu sangat sebagian kecil dari keseluruhan koridor. Melapisi koridor penerbangan di FIG 1-1 adalah amplop operasional berbagai pesawat bertenaga. Batas-batas operasional sistem propulsi setiap ditentukan oleh keterbatasan komponen sistem propulsi dan ditunjukkan pada gambar 1-2.Analisis yang disajikan dalam teks ini menggunakan sifat-sifat suasana untuk menentukan kinerja mesin maupun airframe. Karena sifat ini berbeda dengan lokasi, musim, waktu hari, dll. Kita akan menggunakan standar ASatmosphere (Ref. 2) to give a known foundationl for our analyses. Appendix Agives the properties of the U.S. standrd atmosphere, 1976, in both Englishand SI units. Values of the pressure P, temperature T, density p, and speed ofsound a are given in dimensionless ratios of the property at altitude to itsvalue at sea level (SL), (the reference value). The dimensionless ratios ofpressure, temperature, and density are given the symbols O, and u,The reference values of pressure, temperature, and density are given for eachunit system at the end of its property table.For nonstandard conditions such as a hot day, the normal procedure is touse the standard pressure and correct the density. using the perfect gasrelationship o = 6/6. As an example, we consider a 100°F day at 4-kft altitude.From App. A, we have 8 = 0.8637 for the 4-kft altitude. We calculate 0, usingthe 100°F temperature; O = T/T= (100 + 459.7)/518.7 = 1.079. Note thatabsolute temperatures must be used in calculating 0. Then the density ratio iscalculated using o 6/8 = 0.8637/1.079 = 0.8005.1-4 AIR-BREATHING ENGINESThe turbojet, turbofan, turboprop, turboshaft, and ramjet engine systems arediscussed in this part of Chap. 1. The discussion of these engines is in thecontext of providing thrust for aircraft. The listed engines are not all theengine types (reciprocating, rockets, combination types, etc.) that are used inproviding propulsive thrust to aircraft, nor are they used exclusively onaircraft. The thrust of the turbojet and ramjet results from the action of a fluidjet leaving the engine; hence, the name jet engine is often applied to theseengines. The turbofan, turboprop, and turboshaft engines are adaptations ofthe turbojet to supply thrust or power through the use of fans, propellers, andshafts.Gas Generator The “heart” of a gas turbine type of engine is the gas generator. A schematicdiagram of a gas generator is shown in Fig. 1-3. The compressor, combustor,and turbine are the major components of the gas generator which is commonto the turbojet, turbofan, turboprop, and turboshaft engines. The purpose of agas generator. is to supply high-temperature and high-pressure gas.TUJUHHHHThe TurbojetBy adding an inlet and a nozzle to the gas generator, a turbojet angine can heconstructed. A schematic diagram of a simpte turbojet is shown in Fig. 1-4ò.and a turbojet with afterburner is shown in Fig. 1-45. In the analysis of aturbojet engine, the major components are treated as sections. Also shown inFigs. 1-4a and 1-4b are the station numbers for each sectionDELAPANNNSchematic diagram of a turbojet With afterburner.The.turbojet was first used as a means of aircraft propulsion..bychain (first flight August 27, 1939) and Whittle (first flight May 15, 1941). Asdevelopment proceeded, the turbojet engine became more efficient andreplaced some of the piston engines. A photograph of the J79 turbojet with
afterburner used in the F-4 Phantom II and B-58 Hustler is shown in Fig. 1-5.




SEMBILANNN
The adaptations of the turbojet in the form of turbofan, turboprop, and

turboshaft engines came with the need for more thrust at relatively low speeds.

Some characteristics of different turbojet, turbofan, turboprop, and turboshaft

engines are included in App. B.

The thrust of a turbojet is developed by compressing air in the inlet and

compressor, mixing the air with fuel and burning in the combustor, and

expanding the gas stream through the turbine and nozzle. The expansion of

gas through the turbine supplies the power to turn the compressor. The net

thrust delivered by the engine is the result of converting internal energy to

kinetic energy.

The pressure, temperature, and velocity variations through a J79 engine

are shown in Fig. 1-6. in the compressor section, the pressure and temperature

increase as a result of work being done on the air. The temperature of the gas

is further increased by burning in the combustor.