The turboprop engine is very similar to the turbojet. The difference is that it uses propeller to provide most of its thrust. It is heavier than a turbojet of equivalent size and power. However, its fuel consumption is lower in comparison with a turbojet. A variation of the turboprop engine is known as the turboshaft engine. It is often used for powering helicopters.
The turbofan engine combines the features of both the turbojet and turboprop engines. In the turbofan the propeller is replaced by an axial-flow fan. The turbofan is lighter than a turboprop, it has relatively low fuel consumption. The turbofan as well as the turboprop, produces more thrust than the turbojet during take-off. Turbofans are widely used in aviation, especially in large multi-engine aircraft.
Задания
I. Подберите соответствующие пары из левой и правой колонок, в результате чего Вы получите словарь для перевода текста.
advantage - недостаток
disadvantage, limitation - преимущество
air-breathing engine - турбореактивный двигатель
application - грузоподъемность
belong, v - выбрасывать, выпускать
combustion chamber - камера сгорания
in comparison (with) - сложный
complicated - по сравнению (с)
utilize, v - применение
deliver, v - доставлять
differ (from), v - принадлежать
eject, v - расширять(ся)
essential - входное устройство
expand, v - использовать
feature, n - воздушно-реактивный двигатель
fuel consumption - ракетное топливо (твердое, жиккое)
inlet assembly - выхлопное сопло
load-carrying capacity - основной
nozzle (exhaust, discharge) - расход топлива
propellant (solid, liquid) - (быть) похожим (на)
(be) similar (to) - отличатся (от)
turboshaft engine - черта, особенность
II. Прочтите и переведите текст.
III. Озаглавьте текст на английском языке.
IV. Разделите текст на части по смыслу и передайте их содержание на русском языке в объеме 1-го (2-х) предложений.
V. Образуйте и переведите производные слова согласно образцу :
прилагательное или существительное + ize/ise = глагол
special – специальный – specialize – специализировать (ся)
computer, ideal, crystal, central;
префикс over – (сверх - ; пере - )
to heat – нагревать – to overheat – перегревать
production, active, grow, estimate.
VI. Найдите в тексте синонимы прилагательному “ main” и переведите.
VII. Переведите словосочетания, обращая внимание на
Participle I и Participle II :
Participle I - stabilizing - стабилизирующий
Participle II - stabilized - стабилизируемый
a framework covered with a metal;
a plane covering a distance;
a surface supporting an airplane;
ground forces supported by aviation
sweptback wing providing high speed;
high speed provided by sweptback wing;
the flight controlled by autopilot.
VIII. Переведите предложения, обращая внимание на окончание – ed:
1. Tail surfaces supported an aeroplanes in horizontal flight.
2. The designers as a rule attached a rudder to the fin.
3. An airplane is supported in the air by wings.
4. Landing gear and tail unit are attached to the fuselage
IX. Найдите в тексте предложения, содержащие, причастие I, причастие II и герундий, переведите их и укажите функции.
X. Найдите в тексте предложения, содержащие инфинитив, переведите их и укажите функции.
XI. Назовите английские эквиваленты следующих терминов:
1. воздушно-реактивные двигатели
2. прямоточный двигатель
3. пульсирующий двигатель
4. турбореактивный двигатель
5. турбовинтовой двигатель
6. турбовентиляторный двигатель
7.турбовальный двигатель
8.ракетный двигатель на твердом топливе
9. ракетный двигатель на жидком топливе
XII. Найдите ответы на вопросы:
1.What can you say about the number and location of engines in the aircraft?
2. How are jet engines classified?
3. What is the simplest type of air-breathing engines?
4. Is the pulsejet engine more complicated that the ramjet one?
5. What engines belong to the family of gas-turbine engines?
6. How are turbojets divided?
7. What are essential components of a turbojets?
8. What are the advantages of a turbofan engine?
XIII. Составьте реферат и подготовьте аннотацию текста (см. приложение).
TURBOJET TURBOPROP
1. inlet assembly 1. inlet assembly
2. axial compressor 2. compressor
3. combustion chamber 3. combustion chamber
4. gas turbine 4. gas turbine
5. jet nozzle 5. exhaust unit
6. reduction gearbox
7. propeller
TURBOFAN RAMJET
1. inlet assembly 1. diffuser
2. low-pressure compressor (fan) 2. combustion chamber
3. inner-duct compressor 3. jet nozzle
4. combustion chamber 4. igniters, flame holders
5. turbine 5. fuel injectors
6. jet nozzle
TEМА 7
ФОНЕТИЧЕСКИЕ УПРАЖНЕНИЯ
Упражнение 1. Прочитайте следующие слова и словосочетания:
Turbine, gas turbine, turbine blade, combustion chamber, pressure, temperature, power, сompressor, compression ratio, power-to-weight ratio, accessories, efficient, efficiency, driving torque, stationary nozzle guide vanes.
TEXT
The Gas Turbine
The gas turbine provides the power the compressor and accessories. It does this extracting energy from the hot gases released from the combustion chamber and expanding them to lower pressure and temperature. High stresses are involved in this process, and for efficient operation, the turbine blade tips may rotate at speeds up to 500 meters per second. The continuous flow of gas, to which the turbine is exposed may have an entry temperature of up to 1400*C and may reach a velocity up to 700 meters per second in some parts of the turbine.
To produce the driving torque, the turbine may consist of several stages, each employing one row of stationary nozzle guide vanes and one row of moving blades. The number of stages depends on whether the engine has one shaft or two and also on the relation between the power required from the gas flow, the rotational speed at which it must be produced and the diameter of turbine permitted.
The number of shafts varies with the type of engine. High compression ratio engines usually have two shafts, driving high and low pressure compressors. On high bypass ratio fan engines another turbine is interposed between the high and low pressure turbines, thus forming a triple-spool system.
The bypass engine enables a smaller turbine to be used than in a pure jet engine for a given thrust output and it operates at a higher gas inlet temperature, thereby obtaining improved thermal efficiency and power-to-weight ratio.
The balancing of a turbine is an extremely important operation in is manufacture and maintenance. In view of the high rotational speeds and the mass of materials, any un-balance could seriously affect the rotating assembly bearing and engine operation. Balancing is effected on a special balancing machine and is conducted after each maintenance operation connected with replacements of blades, discs and bearings.
Комментарий к тексту:
1. accessories - вспомогательные средства
2. high stresses - высокие нагрузки
3. continuous flow of gas - непрерывный поток газа
4. entry temperature - температура на входе турбины
5. driving torque - вращающий момент
6. stationary nozzle guide vanes – неподвижные направляющие лопатки соплового
агрегата
7. diameter of turbine permitted - допустимый диаметр турбины
8. high bypass ratio fan engines - вентиляторные двигатели с высоким коэффици-
ентом двухконтурности
9. triple-spool system - трехвальная система
10. for a given thrust output - для данной развиваемой тяги
11. thermal efficiency - тепловая эффективность
12. power-to-weight ratio - удельная мощность
13. bearing - подшипник
14. replacements - замены
Задания
I. Прочтите и переведите текст.
II. Найдите эквиваленты для английских словосочетаний:
1. the gas turbine 1. обеспечивать
2. the combustion chamber 2. удельная мощность
3. to provide 3. давление
4. power-to-weight ratio 4. работа двигателя
5. bearing 5. камера сгорания
6. continuous flow of gas 6. подшипник
7. the pressure 7. вспомогательные средства
8. entry temperature 8. непрерывный поток газа
9. accessories 9. температура на входе турбины
10. engine operation 10. зависеть от
11. depends on 11. газовая турбина
12. thermal efficiency 12. состоять из
13. consist of 13. тепловая эффективность
III. Назовите английские эквиваленты:
Компрессор, камера сгорания, вращающаяся турбина, газовая турбина, давление, подшипник, работа двигателя, удельная мощность, обеспечивать, зависеть от, непрерывный поток газа.
IV. Переведите предложения, обращая внимание на перевод сослагательного наклонения:
It is important that passenger planes should meet passengers requirements in
flight.
The equipment being used on planes should be very accurate and reliable.
To ensure safety the airport should be equipped with the most modern
landing aids.
It was decided that a new landing system would be installed at this airport.
It is important that the method of attachment should be designed carefully.
The construction of the airport should be completed next year.
The best position for the engines would be as far away from the pilot and pas-
sengers as possible.
It is vital that ground crews should thoroughly prepare and inspect every plane
for its flight.
9. We should introduce this method if it were efficient.
V. Скажите соответствуют ли предложения содержанию текста, если нет, то дайте правильный ответ.
1. The gas turbine provides the power the compressor and accessories.
2. To produce the driving torque, the turbine may consist of one stage.
3. The number of stages doesn’t depend on whether the engine has one shaft or two and also on the relation between the power required
4. The number of shafts varies with the type of engine.
5. High compression ratio engines usually have five shafts and high pressure compressors.
6. The balancing of a turbine is an extremely important operation in is manufacture and maintenance.
VI. Ответьте на вопросы по тексту:
1. What is the gas turbine for?
2. Where does the turbine obtain its energy from?
3. At what speeds may the turbine blade tips rotate for efficient operation?
4. What is the entry temperature of the flow of gas to which the turbine is exposed?
5. What velocity may this flow of gas reach?
6. What number of stages may the turbine consist of?
7. What rows does each stage of the turbine consist of?
8. What is the difference between the blades and vanes?
9. On what factors does the number of stages depend?
10.How many stages do high compression ratio engines have?
11. What do these shafts do?
12. On what types of engines are triple-spool system used?
13. What parts does a spool consist of?
14. What are the advantages of bypass engines?
15. What are the results of any unbalance of the gas turbine?
VII. Составьте аннотацию текста.
TEМА 8
ФОНЕТИЧЕСКИЕ УПРАЖНЕНИЯ
Упражнение 1. Прочитайте следующие слова и словосочетания:
Chamber, combustion chamber, combustion area, energy, fuel, fuel nozzle, fuel-air mixture, tube, flume tube, stabilization, flame stabilization, burner, power, source of power, propulsive power, engine, jet engine, turbine engine.
Упражнение 2. Прочитайте и переведите следующие слова и словосочетания:
Arrange, arrangement, available, availability, burn, burner, burning, complete, completely, cool, cooling, cooling system, deliver, delivery, penetrate, penetration,
penetrating.
TEXT 1
The Combustion Chamber
Jet devices are known to use reaction as a source of power. The heat released by burning of a fuel adds energy to the air stream and is considered to be the only ene-rgy to provide propulsive thrust.
The burning of fuel takes place in the combustion chamber. The compressed air from the compressor is extended further into the combustion chamber. To support combustion and obtain propulsive power the jet engines utilize oxygen from the sur-rounding atmosphere. Roughly one-fourth of the air entering the combustion area is burnt with the fuel. The purpose of the combustion chamber is to deliver the heat to the passing through the engine.
Each combustion chamber is supplied with fuel through fuel nozzles mounted at the forward end of the chamber. The design and arrangement of fuel nozzles have an important effect on the operation of any combustion chamber. Many different types of fuel nozzles are employed in modern turbine engines.
Primary air enters the chamber through guide vanes arranged around the fuel nozzles. The vanes cause the air to flow with a swirling motion which aide in good mixing of fuel and even burning. The design of vanes helps to bring about complete burning of the fuel before the fuel-air mixture leaves the chamber. The mixture of fuel and air is ignited by means of spark plugs (or igniters).
As a result of the burning the temperature of the fuel-air mixture is considerably increased. To reduce the temperature of the hot gases entering the turbine, the quantity of air entering the combustion chamber, as was mentioned before, is about four times as much as needed for combustion of the fuel.
To provide a correct mixture for burning the primary air is mixed with the fuel in the combustion- chamber flame tube. After burning is completed secondary air joins the burning mixture to provide cooling.
Each combustion chamber comprises two principal parts termed the inner liner and the outer liner. Burning of fuel takes part directly in the inner liner. Even though extremely high temperatures exist where the burning takes place, the secondary air flowing between the inner liner and the outer liner prevents the heat from the penet-rating to the outer liner. The secondary air also cools the inner liner by flowing along the outside of the inner liner and entering the liner through holes and louvers.
There are three basic types of combustion chambers available:
1. The Individual Combustion Chamber.
The design of individual or “can” type combustion chambers may seem to be rather simple. One of the most important characteristics of this combustor to the flame stabilization, that is, the smooth continuous ignition process. One of the advantages of having individual combustion chambers is that replacement of combustion chamber is possible without complete engine disassemblying.
2.The Annual Combustion Chamber.
Basically , an annual combustion chamber is a single chamber completely surro-unding the engine. Fuel is fed to the front end of the burner by means of a ring of a number equally spaced fuel nozzles. The annual chamber has important advantages.
A large volume is available in proportion of the inner exposed area.
3. The Cannular Combustion Chamber.
The cannular or “can-annular” combustion chamber is a combustion of the “can” type and the annual type. This burner consists of some combustion chambers or “cars” arranged evenly around the circumference of an annular chamber. Each separate burner is in the form of a small annular chamber, in that there is inner liner through which air flows to cool the inside of the chamber.
Комментарий к тексту:
1. as a result - в результате
2. as was mentioned before - как упоминалось выше
3. even though - даже если
4. is about four times as much as needed - примерно в 4 раза больше, чем необходимо
5. around the circumference - по окружности
6. an exposed area - занимаемая площадь
Задания
I.Назовите русские эквиваленты:
some combustion chambers
to use reaction as a source of power
to provide propulsive thrust
the surrounding atmosphere
the air entering the combustion chamber
to deliver the heat to the passing through the engine
the forward end of the chamber
the design and arrangement of fuel nozzles
as a result of the burning
to reduce the temperature
the hot gases entering the turbine
two principal parts
to provide a correct mixture for burning
one of the advantages
II. Найдите в тексте английские эквиваленты:
В результате горения температура топливовоздушной смеси значительно увеличивается.
Хорошее горение топлива и ровное горение.
Обеспечивать хорошую смесь для горения.
Иметь преимущества.
Тепло, получаемое в результате сгорания топлива.
Обеспечить хорошую смесь для горения.
III. Переведите предложения, обращая внимание на сложное дополнение:
I know him to be a good designer. 2.She saw him repairing the engine before the
flight. 3.We watched the plane land. 4. I believe him to be a very good pilot.
5. They allow to use dictionaries at the examination. 6. Tests showed this type of engine to be very efficient. 7. We know every modern airplane to be equipped with certain radio devices. 8. We want this aircraft equipment to function properly.
IV.Укажите, какие утверждения соответствуют содержанию текста. Исправьте неправильные утверждения.
Jet devices are known to use reaction as a source of power.
The burning of fuel takes place in the compressor.
The compressed air from the compressor is extended further into the combustion chamber.
Many different types of flame tube are employed in modern turbine engines.
Primary air enters the power plant through guide vanes arranged around the fuel nozzles.
As a result of the burning the temperature of the fuel-air mixture is considerably reduced.
7. The annual chamber has some important disadvantages.
V. Просмотрите текст и ответьте на вопросы.
1. What is this text about?
2. Where does the burning of fuel take plane?
3. What does the jet engines utilize from the surrounding atmosphere?
4. What is the purpose of the combustion chamber?
5. Are many different types of fuel nozzles employed in modern turbine engines?
6. What types of combustion chamber do you know?
7. How many parts does each combustion chamber comprise?
8. Do the design and arrangement of fuel nozzles have an important effect on the ope-
ration of any combustion chamber?
9. What advantages do individual combustion chambers have?
10.What can you say about an annual combustion chamber?
11. Does an annual combustion chamber have important advantages?
12. What important advantages does an annual combustion chamber have?
13. If you are interested in higher fuel efficiency and lesser air pollution, which type of combustion chamber would you choose?
VI. Составьте реферат текста.
TEXT 2
The Turbine
Any gas turbine consists of the turbine nozzle and turbine wheel. The flow of the hot gases from the combustion chamber is directed to the turbine nozzle. When there is more than one turbine wheel additional turbine diaphragms are installed in order that the heated gases might be directed from one wheel to the next.
The extraction of power from the jet stream of the engine for driving the compressor and accessories is the principal function of the turbine wheel. The usual
turbine wheel assembly consists of a shaft, a wheel or disk, and the buckets (blades) fastened to the rim of the disk.
The method for attaching the buckets to the turbine wheel rim must be designed so that the strength, low stress concentration, simplicity and case of replacement in the field may be provided.
Though turbine buckets may be attached to the turbine wheel rim by a variety of methods, it appears that the fir-tree attachement is the most satisfactory and the most widely used. One of the reasons for the design of the “fir-tree” attachement is the temperature differential between the rim wheel and the buckets. The “fir-tree” attachément consists of a series of grooves broached on the root of the bucket and in the rim of the wheel. During operation, the expansion of the metal causes the bucket root to fit tightly is the rim of the wheel.
Turbine blades are made in two principal configurations: shrouded and unshrouded. The shrouded bucket is provided with a shroud section at the outer ends of the blades.
With the unshrouded blades, it is necessary that a closely fitting shroud ring should be provided to prevent the escape of the hot gases which drive the turbine. Turbine buckets must be designed so that they could withstand a variety of severe condition and forces such as heat, centrifugal force, thermostress, varying atmosphere, corrosion, vibration and differential expansion of materials. These conditions should be taken into account in the design of such construction as gas turbine.
To achieve reliability, efficiency and long life for buckets, the following points must be controlled carefully during manufacture: (1) grain structure of the material, (2) aerodynamic performance, (3) surface finish, and (4) producibility.
The turbine wheel appears to be the most stressed component of a gas turbine engine. The buckets of the wheel are subjected to high centrifugal stresses and to a stream of hot gases. The disk of the wheel is subjected to heat by conduction from the buckets and may, in some cases, be directly heated by the combustion gases. Turbine disks are cooled by means of air bled from the compressor section and directed through passages to flow around the turbine disk.
The discharged gases from the turbine wheel are collected and expelled at the correct velocity by the exhaust cone which is located directly behind the turbine wheel.
Комментарий к тексту:
case of replacement in the field - легкость замены в условиях эксплуатации
such as - такой как, как например
in some cases - в некоторых случаях
in case - в случае
in any case - во всяком случае
to take into account - принимать во внимание
Задания
Прочитайте и переведите текст.
2. Составьте реферат текста.
3. Составьте аннотацию текста.
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