Навчальний посібник з англійської мови за професійним спрямуванням "Professional English. Aircraft Design and Maintenance"




Скачати 11,72 Mb.
Сторінка19/31
Дата конвертації09.09.2018
Розмір11,72 Mb.
1   ...   15   16   17   18   19   20   21   22   ...   31

S. Let me see. There are nine rows of blades or stages.

T. Yes, this is the “9-stage” compressor because of the 9 rows of the compressor blades. As in the centrifugal compressor the rotor is mounted by two bearings: a roller bearing and a ball bearing. The axial compressor stator consists of two half cylinders. You can easily guess the meaning of the words “cylinder" and “half cylinder”.

S. They are translated as “циліндр/цилиндр” and “напівциліндр / полуцилиндр”.

Т. Good. These two half cylinders are bolted through flanges (фланець / фланец). Can you translate: “to bolt through flange”?

S. “Закріплювати болтами через фланець / Крепить болтами через фланц”.

T. That's correct. The stator blades are used to redirect the air from one stage to the next. You know the meaning of the word “to direct” – направляти / направлять. The prefix “re-” means “nepe-”. What is the Ukrainian / Russian for “redirect” then?

S. I think “переспрямовувати, змінювати напрям / перенап-равлять, изменять направление ”.

T. Right you are. These stator blades can be shrouded (бандажований / бандажированный) and unshrouded. Рrefix “un-” supplies the negative meaning to the word. So, what is “unshrouded”?

S. Heбандажований / Hебандажированный.

T. That's correct.
Exercise 31. Read, translate and give the gist of text 5.

Text 5. Axial-Flow Compressor

The axial-flow compressor has two main elements: the rotor and stator. In a single-stage compressor the compressor, shaft, and turbine all rotate together as a single unit. In a multi-stage or multi-spool engine the turbine shafts are attached to their respective compressors coaxially, that is one within the other. The rotor of axial compressor consists of several bladed disks shrunk on the shaft. Each row of rotor blades constitutes a stage. The number of stages in the axial compressor varies with the engine design. The typical compressor of this type consists of 11 bladed disks shrunk on a steel shaft and is enclosed in an outer casing. It is called an “11-stage” compressor because of 11 rows of compressor blades. Modern axial-flow engines may have as many as 17 stages. As in the centrifugal compressor the rotor is mounted by two bearings: the roller bearing and the ball bearing. The axial compressor stator consists of two half cylinders bolted together through flanges along the edges. The two halves of them form the cylinder which is the compressor casing. The stator blades are used to redirect the air from one stage to the next. They are constructed in the same manner as the rotor blades and have a similar shape. They can be shrouded and unshrouded. As to disadvantages we may speak about difficulty of manufacture, high cost, relatively high weight, low pressure rise per stage. But this type of compressor has high efficiency at small frontal area and as a result low drag.


Exercise 32. Translate the adverbs.

Continuously, completely, experimentally, manually, permanently, simply, slowly, smoothly, substantially, alternatively, badly, directly, hardly, incidentally, nec­essarily, occasionally, previously, properly, readily, nearly, really, unfortunately, aerodynamically, astronomically, geographically, mathematically, mechanically, physically, physiologically, scientifically, symmetrically, technologically, theoreti­cally.


Exercise 33. Translate the following word combinations paying attention to the italicized adjective-noun pairs.

Hot body – heat of a body, deep knowledge – depth of a river, long road – length of a road, wide river – width of a river, high ceiling – height of a ceiling, strong construction – strength of a construction.

Exercise 34. Translate the derivative chains.

To direct-director-direction; to compress-compressor-compres-sion; to rotate-rotor-rotation; to design-designer; to form-formal-formation; to use-usage-useful-useless; to operate-operator-operation, provide – provider – provision.



Exercise. 35. Answer the questions on text 5.

1. What are two main elements of the axial-flow compressor?


2. What rotates together as a single unit? 3. What con­sists of several bladed disks shrunk on the shaft? 4. What constitutes a compressor stage? 5. What defines the number of stages in the axial-flow compressor? 6. What does the axial compressor stator consist of? 7. What consists of two half cylinders? 8. What is mounted by means of two bearings? 9. What are two types of bearings? 10. What do the stator blades redirect? 11. What are the advantages and disadvantages of an axial compressor?
Exercise 36. Translate the word combinations in column B.


A

B

Admit- дозволяти / позволять; допускати / допускать

admission of air -

add – додавати / добавлять

additional fuel -

transmit - передавати / передавать

pressure transmission -

generate - створювати / создавать

energy generation -

eject - викидати / выбрасывать

gas ejection -

diffuse - розсіювати / рассеивать

axial diffuser -

сonsume - споживати / потреблять; витрачати / расходовать

fuel consumption -

heat - нагрівати / нагревать

heated gases -

release – вивільняти / высвобождать; виділяти / выделять

released heat -

augment - підсилювати / усиливать; збільшувати / увеличивать

thrust augmentation -

pass - проходити / проходить

air passage -

require - вимагати / требовать

required conditions -


Exercise 37. Fill in the blanks with the following terms: bladed disks, flanges, unshrouded, the rotor, stator, bearings, half-cуlinders, сasing.

1. The axial-flow compressor consists of ... and ... . 2. The rotor of axial-flow compressor consists of several ... ... . 3. The rotor is mounted by means of two ... . 4. The axial-flow compressor stator consists of two … . 5. The two halves are bolted together through ... .


6. The cylinder is the compressor ... . 7. The stator blades can be shrouded and ... .
Exercise 38. Look at the picture (Fig. II.2.5) and memorize the names of the main engine components.

Fig. II.2.5. Turbojet Engine

1. air intake – повітрозабирач / воздухозаборник

2. centrifugal flow compressor – відцентровий компресор / центробежный компрессор

3. combustion chamber – камера згорання / камера сгорания

4. gas turbine – газова турбіна / газовая турбина

5. exhaust nozzle – вихлопне сопло / выхлопное сопло

6. shaft – вал / вал


Exercise 39. Study the picture (Fig. II.2.6) and give English equivalents.

Fig. II.2.6. Turbojet Engine

1. Повітрозабирач / воздухозаборник -

2. Осьовий компрессор / осевой компрессор -

3. Камера згорання / камера сгорания -

4. Газова турбіна / газовая турбина -

5. Форсажна камера / форсажная камера -

6. Вихлопне сопло / выхлопное сопло


Exercise 40 . Translate into English.

1. Осьовий компресор склада-ється з ротора і статора.

1. Осевой компрессор состоит из ротора и статора.

2. В одноступеневому компре-сорі всі його рухомі елементи обертаються разом як одне ціле.

2. В одноступенчатом компрес-соре все его движущиеся эле-менты вращаются вместе как одно целое.

3. Декілька дисків з лопатками насаджуються в гарячому стані на вал.

3. Несколько дисков с лопатками насаживаются в горячем состоянии на вал.

4. Ротор oсьового компресора складається з декількох дисків з лопатками.

4. Ротор осевого компрессора состоит из нескольких дисков с лопатками.

5. Кожен ряд лопаток ротора складає один ступінь.

5. Каждый ряд лопаток ротора составляет одну ступень.

6. Ротор монтується за допо-могою двох підшипників – куль-кового та роликового.

6. Ротор устанавливается при помощи двух подшипников – шарикового и роликового.

7. Два напівциліндри статора утворюють кожух компресора.

7. Два полуцилиндра статора образуют кожух компрессора.

8. Лопатки статора переспрямовують потік повітря від одного ступеня на інший.

8. Лопатки статора перенап-равляют поток воздуха от одной ступени к другой.

9. За конструкцією лопатки можуть бути бандажовані та небандажовані.

9. По конструкции лопатки могут быть бандажированными и небандажированными.

10. До переваг осьового компресора відносяться його висока ефективність при невеликій фронтальній площі та низький лобовий опір.

10. К преимуществам осевого компрессора относятся его высокая эффективность при небольшой фронтальной площади и низкое лобовое сопротивление.

Exercise 41. Memorize the active vocabulary.

spool

каскад

каскад

two-spool compressor

двокаскадний компресор

двухкаскадный компрессор

separate

1. окремий 2. відокрем-лювати

1. отдельный 2. отделять

hollow

пустотілий,порожнистий

пустотелый, полый

proper

відповідний, правильний

соответствующий, правильный

govern

керувати

управлять

alloy

сплав

сплав

unsteady flow

1. нестаціонарний потік 2. неусталена течія

1. нестационарный поток 2. неустановившееся течение

robust

жорсткий; міцний (про конструкцію)

жесткий; прочный (о конструкции)

couple

1. пара сил; момент пари сил 2. з’єднувати; зв’язувати

1. пара сил; момент пары сил 2. соединять, сцеплять; связывать


Exercise 42. Practise out the dialogue.

Dialogue

T. And now let's proceed to the third type of the compressor – the axial-split compressor type. Look at the picture (Figure II.2.7). This is a typical two-spool compressor. Spool is каскад/каскад. It consists of two rotors: a low-pressure rotor (N1) and a high-pressure rotor (N2). How many stages are there in the low pressure compressor?

S. There are two stages .

T. Right you are. This low-pressure compressor is made up of two stages. And what about the high-pressure compressor? How many stages does it have?

Fig.II.2.7 Two-spool compressor



S. It has 5 stages. It is a five-stage compressor.

T. That's good. Two compressor rotors in a two-spool system are mounted on separate shafts. The shaft of the rear rotor is hollow (порожнистий / пустотелый, полый). What is the English for “порожнисті лопатки / пустотелые лопатки”?

S. “Hollow vanes”.

T. Right. The front rotor shaft passes through the hollow shaft of the rear rotor. Between the two rotors of the two-spool compressor there are guide vanes. They give proper direction to the air flow from the low-pressure section to the high-pressure section. Will you translate "low-pressure section” and “high-pressure section”, please?

S. ”Секція низького тиску/секция низкого давления” та/исекція високого тиску/секция высокого давления ”.

T. Great! Thank you.
Еxercise 43. Read, translate and give the gist of text 6.

Text 6. Axial-Split Compressor Type

The axial-split compressor consists of two rotors. One is a low-pressure rotor, the other is a high-pressure rotor. The high pressure rotor causes pressure rise in the air leaving the low pressure rotor. Two-spool compressors are used in both turbojet and turboprop engines. The high-pressure rotor is governed for speed, and the low-pressure rotor is free to operate at its own best speed. The two compressor rotors are mounted on separate shafts. Each rotor has the front and the rear bearings. The rear bearing for each rotor is a ball bearing. The compressor rotor is supported by the roller bearing at the front. The compressor rotor consists of steel bladed disks. The compressor blades are made of forged alloy steel and are mounted on the rim of the disks. Between the two rotors of the two-spool compressor there is a supporting structure for rotor bearings and guide vanes. The guide vanes are designed to give proper direction to the airflow from the low-pressure section to the high-pressure section. Since the two-spool engine is designed for high-power and high pressure ratios most of the parts are constructed of alloy steel instead of alluminium alloy.


Eхercise 44. Answer the key questions on text 6.

1. What does the axial-split compressor consist of? 2. What rotor is governed for speed? 3. What rotor is free to operate at its own best speed? 4. Where are guide vanes located? 5. What are the compressor parts made of? Why? 6. What is the compressor rotor supported by?


7. Do we mean one and the same type of a compressor speaking about an axial split and two spool compressor?
Exercise 45. Match the terms with their definitions.

1. inlet guide vanes

a) The forward moving force produced by a propeller or a jet or rocket engine as exhaust gases are expelled through the exhaust nozzle.

2. afterburner

b) An entrance or orifice for the admission of air into the compressor.

3. air intake

c) A duct or tube through which the gases produced in the combustion chamber are accelerated and discharged.

4. exhaust cone

d)The part of the gas turbine engine where combustion of air-fuel mixture takes place.

5. turbine

e) A device for augmenting the thrust of a jet engine by burning additional amount of fuel in the gases from the turbine.

6. combustion chamber

f) A rotating member for transmission of power.

7. fan

g) A part of an engine between the compressor and combustion chamber for reducing the airflow speed and increasing the air pressure.

8. diffuser

h) The element that provides the major portion of thrust in a turbofan engine.

9. thrust

i) A fixed set of blades in front of an engine compressor for directing airflow to the compressor.


Exercise 46. Translate the following word combinations containing Past Participle.

Increased vibration, reduced air consumption, compressed fuel-air mixture, required air supply, acquired test data, predicted discharge coefficient, reduced airflow speed, increased air mass, needed temperature measurement, calculated ambient condition, simplified chamber design, measured exhaust pressure, eliminated pressure fluctuation, lowered noise level, modified compressor outlet, required inlet air temperature, caused by high pressure, constructed of aluminum alloy, mounted on a shaft, designed to carry loads, supported by bearings, governed for speed, made of forged alloy steel, produced by a fan, burned in the combustion chamber, expelled through the exhaust nozzle, admitted into the compressor.


Exercise 47. Give definitions of the following terms: inlet guide vanes, afterburner, air intake, exhaust cone, turbine, combustion chamber, fan, thrust, diffuser.
Exercise 48. Put questions of different types to the italicized words.

1. Each row of blades constitutes a stage. 2. The axial-flow compressor consists of two rotors. 3. The two compressor rotors are mounted on separate shafts. 4. Most of the parts are constructed of alloy steel. 5. The guide vanes give a proper direction to the airflow. 6. The compressor blades are mounted on the rim of the disk.


Exercise 49. Write a brief summary of text 6 in your own words.
Exercise 50. Read, translate and give the gist of text 7.
Text 7. Compressor Requirements

The compressor must satisfy a number of requirements if it is to be suitable for use in a gas turbine.

It is required to raise the entry air pressure by an amount depending on the cycle being used. The pressure ratio across the compressor may be anything from 3 or 4:1 to as much as 20 or 30:1. The higher pressure ratios cannot be developed in a single unit, and a number of units in series must be used. This compression must be effected with as little loss as possible; for the greater the loss the more power must be supplied by the turbine driving the compressor. In general the losses in a compressor vary with the conditions under which it is being operated. It is clearly important therefore that the conditions under which these losses are low and the efficiency therefore is high should correspond as closely as possible to those under which the compressor will have to operate in the complete gas turbine system. In most forms of compressor there is a region of instability in which unsteady flows occur. It is most desirable and usually essential that the compressor should not be required to operate in this region.

These are the most important general aerodynamic requirements to the compressor. There are of course special requirements in addition to many of the specific application of the gas turbine. For example, in the compressor of the aircraft turbine engine, the compressor must be as compact and light as possible and must be able to deal with as much air as possible in a given frontal area.


Exercise 51. Put 5 key questions on text 7.
Exercise 52. Read, translate and give the gist of text 8.
Text 8. Pros and Cons

There are a number of different types of compressor that could be used in a gas turbine, and each has something to be said for and against it.

The axial compressor has so far been used more than any other type and is likely to remain in favor. Its principal and overwhelming advantage is that it can develop a higher efficiency than any other type. From the aircraft point of view it has the further advantage of low frontal area for a given air flow. At the present time, however, it is comparatively expensive to make owing to its large number of blades. The pressure ratio that can be developed in a single unit axial compressor is probably fairly high – at least 12:1. But the characteristics of such a compressor would be quite unsuitable for use in a gas turbine, and starting would be impossible without motoring the unit up to a speed well over half the design speed. It is not yet known for certain what is the highest pressure ratio that can be developed in practice while still retaining a flexible engine. It is at least 8:1 and may with further knowledge be as high as 10:1. The actual value is probably only of academic interest. A design of a multi-stage axial compressor is mostly for industrial use.

The centrifugal compressor is a more robust machine than the axial and less susceptible to dirt and other foreign bodies. Although its efficiency is lower, the variation of its efficiency with air flow is less than in the axial so that matching of a number of stages in series is easier.


Exercise 53. Discuss the main advantages and disadvantages of the centrifugal and axial compressors types with your groupmates.
Exercise 54. Translate text 9 in a written form and entitle it.
Text 9

The gas turbine engine consists of a rotary air compressor with an air intake, one or more combustion chambers, a turbine, and an exhaust outlet. There are two basic types of rotary air compressors, one giving a centrifugal flow and the other an axial flow. Both types are driven by the engine turbine and are coupled directly to the turbine shaft. The centrifugal flow compressor is a single or two-stage unit employing an impeller to accelerate the air and a diffuser to produce the required pressure rise. The axial flow compressor is a multi-stage unit employing alternate rows of rotating and stationary blades to accelerate and diffuse the air until the required pressure rise is obtained. The centrifugal compressor is usually more robust than the axial compressor and is also easier to manufacture. The axial compressor, however, consumes far more air than a centrifugal compressor of the same frontal area and can also be designed for high pressure ratios much more easily. Since the airflow is an important factor in determining the amount of thrust, this means that the axial compressor engine will also give more thrust for the same frontal area.


Exercise 55. Answer the questions on text 9.

1. What does the gas turbine engine consist of? 2. What is the principle of the centrifugal flow compressor operation? 3. What does the axial flow compressor look like? 4. How can pressure ratio of the axial flow compressor be increased? 5. What are the compressors driven by? 6. What are both compressor types coupled to? 7. What is an important factor in determining the amount of thrust? 8. What are the advantages and disadvantages of the centrifugal flow compressor?


Exercise 56. Speak on:

1.The Compressor: Types and Functions.

2. The Centrifugal Compressor.

3. The Axial-Flow Compressor.



4. The Axial-Split Compressor.
1   ...   15   16   17   18   19   20   21   22   ...   31


База даних захищена авторським правом ©uchika.in.ua 2016
звернутися до адміністрації

    Головна сторінка