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Файл:Jet Propulsion Engine Fundamentals английский язык для студентов специальности «Проектирование авиационных и ракетных двигателей». Учебное пособие
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Booster-stage systems can be used for either storable or cryogenic propellants.
The tanks, arranged in tandem, form walls of the vehicle structure. For booster
application, overall vehicle systems optimization usually dictates use of a turbopumpfed engine system (двигатель с турбонасосной системой подачи топлива). This
permits relatively low operational tank pressures, ranging from 30 to 100 psia. The
tanks represent a large percentage of the vehicle structural (inert) weight. Low
pressure levels allow constructing the tanks with extremely thin walls. However, the
often huge tank structures thus become sensitive to external buckling loads. To
stabilize the tank structures of large booster-stage systems, two basic design avenues
(способы) are open: pressure-stabilization and self-supporting structures
(самонесущие конструкции). In pressure-stabilized systems, such as the Atlas
ICBM, tank pressures must be constantly maintained above a specific minimum by
elaborate (сложный, прецизионный) controls. Atlas’s tank structure, basically a
thin-wall monocoque (моноблок, монококовая конструкция), requires special
handling procedures. In most booster-stage systems, the propellant tanks are selfsupporting, with tank walls reinforced by skin stringers (обшивка, подкрепленная
стрингерами) or by other structural means, such as waffle-grid (вафельный)
patterns. Cryogenic propellants may require tank insulation. It will be mandatory in a
liquid hydrogen system to prevent ambient-air liquefaction (ожижение воздушной
среды), which causes high heat-transfer rates, with attendant high boiloff
(испарение) rates, and safety hazards (угрозы).
In upper-stage system, an outer cylindrical shell, designed to withstand all
anticipated boost (разгон) and flight loads, contains the tanks. The propellant tankage
consists of two individual welded aluminum-alloy tanks, modified spheres, faired
(плавно переходящий) into conical sections at the bottom for propellant discharge.
The tanks are bolted to the shell structure around their support ring (опорное
кольцо). Many upper-stage vehicles employ a gas-pressurized propellant feed
system. Tank pressures range from 100 to 400 psia. The gas for pressurization is
stored at an initial pressure level from 4500 to 5500 psia at – 300⁰ F in two liquidnitrogen-jacketed (охлаждаемый жидким азотом), high-pressure spherical tanks
located between the two main propellant tanks.
Task 12. Answer the questions and use them as a plan for retelling the text.
1. What does the configuration of propellant tanks depend on?
2. What is a main characteristic of prepackaged storable-liquid system?
3. What must the tank walls in prepackaged storable-liquid system withstand?
4. What methods are applied to stabilize the tanks?
5. When is it preferable to employ prepackaged storable-liquid system?
6. What type of propellants can booster-stage system be used for?
7. What is a design configuration of the tanks in booster-stage system?
8. What type of feed system is necessary for booster application?
9. Why is tank structures sensitive to external buckling loads?
10. What is applied to stabilize the tank structures of large booster-stage
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systems?
1. propulsion system
2. propellant tankage
3. integration
4. prepackaged storable-liquid system
1. совместимый
2. двигатель с турбонасосной
системой подачи топлива
3. перегородка
11. What are the major constructive characteristics of the propellant tanks in
most booster-stage systems?
12. Where are the tanks located in upper-stage system?
13. What does the propellant tankage consist of?
14. What type of feed system do many upper-stage vehicles employ?
15. Where and under what conditions is the gas for pressurization stored?
Task 13. Translate the following sentences into English.
1. В качестве вытесняющего газа обычно используют гелий и азот.
2. При насосной системе подачи топлива для подавления кавитации в насосе
необходимо создать в баке небольшое избыточное давление.
3. При использовании криогенного ракетного топлива для подавления
кавитации в насосе применяют нагрев и преобразование в пар небольшого
количества ракетного топлива из выходящей из насоса струи под высоким
давлением и подачу его в топливный бак.
4. Вытесняющий газ не должен конденсироваться или растворяться в
жидком ракетном топливе или вступать в химическую реакцию с его
компонентами.
5. Для вытеснения кислорода и четырехокиси азота применяется гелий.
6. Поскольку вытесняющий газ теплее криогенной жидкости, в результате
теплопередачи газ охлаждается, что приводит к увеличению его плотности.
7. При подаче топлива химическим аккумулятором давления образование
вытесняющего газа происходит в результате процесса сгорания в топливном
баке.
8. Можно достичь существенного снижения количества газа и инертной
массы вытеснительной системы за счет использования горячего газа из
порохового аккумулятора давления или за счет разложения однокомпонентного
ракетного топлива.
9. Решить проблему внезапного охлаждения горячего вытесняющего газа
можно путем физического разделения горячего активного газа и жидкого
ракетного топлива посредством поршня или мягкой мембраны.
10. Вытесняющий газ используют, главным образом, для вытеснения
компонентов ракетного топлива из топливных баков, а также для работы
клапанов и систем управления.
Task 14. Find the Russian equivalents for the English terms.
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5. booster-stage
6. construction materials
7. load
8. specified
9. handling
10. isolation valve
11. vehicle structure
12. compatible
13. percentage
14. pressure loads
15. self-supporting structures
16. pressure-stabilized system
17. upper-stage
18. waffle-grid
19. boiloff
20. tension loads
21. support ring
22. burst disk
23. ambient-air liquefaction
24. turbopump-fed engine system
25. integral part
26. liquid-nitrogen-jacketed tank
27. skin stringers
28. bulkhead
29. buckling
30. containment
4. растягивающие нагрузки
5. система, стабилизируемая
наддувом
6. ускоритель, головной (разгонный)
блок, последняя (верхняя) ступень
7. ожижение воздушной среды
8. единое целое
9. испарение
10. разрушающаяся мембрана
11. двигательная система (установка)
12. топливный бак, охлаждаемый
жидким азотом
13. обшивка, подкрепленная
стрингерами
14. хранимая в заправленном
состоянии двигательная установка
15. оболочка
16. самонесущие конструкции
17. потеря устойчивости
18. опорное кольцо
19. емкость (система) топливных
баков
20. конструкция (летательного)
аппарата
21. вафельный
22. клапан отсечки
23. нагрузка
24. доля
25. стартовая ступень, ступень
ракеты-носителя
26. обслуживание, погрузочноразгрузочные работы
27. монтаж, стыковка (частей ракеты)
28. заданный
29. конструкционные материалы
30. нагрузки от давления
Task 15. Look through the texts (Task 7, 11) and find key sentences in each
paragraph.
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Task 16. Write a summary to the text (Task 7)
Task 17. Sum up the text (Task 11).
Task 18. Skim the text and try to understand its subject matter.
Systems optimization within the overall vehicle design greatly influences tank
design. A principal vehicle-design objective will be highest payload and/or velocity
increment with maximum possible reliability. Design details depend largely upon
type of propellants, mission requirement and configuration, propulsion-system
design, and available construction materials and fabrication techniques.
Propellant Properties. Propellants affect tank design mainly by their physical and
chemical characteristics. The boiling point or storage temperature of a propellant
determines the operating temperature range of the tank assembly. Cryogenic
propellants cause tank design problems due to thermal gradients, the need for
insulation, and need for construction materials capable of remaining ductile at very
low temperatures. The low density of some propellants, such as liquid hydrogen,
necessitates tanks of considerable volume. The highly corrosive and reactive
properties of other propellants severely limit the selection of tank materials.
Shape and Size of Propellant Tank. As a propellant tank, a sphere offers the
smallest surface-to-volume ratio and the smallest shell stress for a given internal
pressure, but the combination of several spheres into the generally cylindrical
envelope typical for most rocket vehicles causes sizable weight and volume penalties.
Furthermore, a sphere precludes use of the tank wall as a load-carrying member of
the vehicle structure, resulting in further weight and volume penalties. Thus, both
vehicle configuration and tank pressure will determine the shape of propellant tanks.
Vehicles of relatively large length-to-diameter ratios and of limited space envelopes
will use cylindrically-shaped tanks. Relatively high tank pressures and less stringent
space conditions may favor spherical tanks. The ends of cylindrical tanks can have
either spherical or ellipsoidal shapes. The basic cylindrical tank with spherical ends
weighs less than one with ellipsoidal ends; but overall, an ellipsoidally-ended tank
may weigh less owing to shorter interstage structure. In some designs, the propellanttank ends will have special shapes to accommodate structural loads, minimize
residual propellants, and utilize available envelope.
Task 19. Choose the right variant to fill in the gap.
1. Systems optimization within the overall vehicle design greatly influences
___________ .
а) propellant tank
b) tank design
c) tank reliability
2. The boiling point or storage temperature of a propellant determines the
operating __________ range of the tank assembly.
a) procedure
b) pressure
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c) temperature
3. Cryogenic propellants cause tank design problems due to thermal gradients, the
need for insulation, and need for construction materials capable of remaining ductile
at very ________ temperatures.
a) moderate
b) low
c) high
4. The low density of some propellants, such as liquid__________, necessitates
tanks of considerable volume.
a) hydrogen
b) nitrogen
c) oxygen
5. The combination of several spheres into the generally cylindrical envelope
typical for most rocket vehicles causes sizable __________ penalties.
a) weight and strength
b) weight and volume
c) weight and size
6. Both vehicle configuration and tank pressure will determine __________ of
propellant tanks.
a) the shape
b) the weight
c) the volume
7. Vehicles of relatively large length-to-diameter ratios and of limited space
envelopes will use ________ tanks.
a) oval-shaped
b) cylindrically-shaped
c) square-shaped
Task 20. Collect all the possible supplementary information on the theme of Unit
7 and present it to your groupmates.
UNIT 8. Turbopump Feed Systems and Engine Cycles
TEXT: TURBOPUMP FEED SYSTEMS AND ENGINE CYCLES
Grammar: The Infinitive
Task 1. Study the forms and functions of the Infinitive in the English sentences
and translate them into Russian.
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Forms
Transitive verbs
Intransitive verbs
Active
Passive
Active
Simple
to write
to be written
to go
Progressive
to be writing
-
to be going
Perfect
to have written
to have been
written
to have gone
Perfect Progressive
to have been
writing
-
to have been going
The function of the Infinitive
Example
Subject
It is permissible to use most of the
common liquid propellants for some
cycles.
Predicative
The main task for a designer is to select
the ‘best’ cycle on the basis of the
mission, the suitability of existing
engines, and the criteria established for
the particular vehicle.
Part of the compound verbal predicate
Both methods can provide a small
amount of additional thrust.
Object to verbs and adjectives
The rocket pump driven directly by the
jet engine makes it possible to increase
aircraft performance.
Attribute
The turbine exhaust to be aspirated into
the main flow through openings in the
nozzle section protects the walls near the
nozzle exit from high temperatures.
Adverbial modifier of purpose or result
In closed cycles all the working fluid
from the turbine is injected into the
engine combustion chamber to make the
most efficient use of its remaining
energy.
Task 2. Find the Infinitive in the English sentences and translate them into Russian.
Pay attention to the ways it is expressed in Russian sentences.
1. From the turbopump feed system options the designer can select the most
suitable concept for a particular application.
2. Heat absorbed by the thrust chamber cooling jacket gasifies and raises the gas
temperature of the hydrogen so that it can be used to drive the turbine.
3. Thrust is regulated by controlling the flow of hydrogen gas to the turbine, using
a bypass to maintain constant chamber pressure.
4. An open cycle can allow a relatively simple engine, lower pressures, and can
have a lower production cost.
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Task 3. Study the following words and word combinations and learn them by heart.
to aspirate – всасывать
augmentation – увеличение,
повышение
diverging – расширяющийся
expander cycle – схема ЖРД без
газогенератора, безгенераторная схема
flow path – траектория потока
gas generator cycle –
газогенераторный цикл (схема ЖРД с
газогенератором, открытая схема
ЖРД)
gas generator mixture ratio –
соотношение компонентов топлива
для газогенератора
handling – зд. удаление
low-area-ratio nozzle – сопло с малой
степенью уширения
mission – цель, назначение
nozzle throat – горло сопла,
минимальное сечение сопла
performance – характеристики
power – мощность
pressure ratio – степень расширения,
перепад давлений
specific – расчетный
specific impulse – удельный импульс
staged combustion cycle – замкнутая
схема (питания ЖРД)
sustainer – ракетный двигатель
маршевой ступени
suitability – пригодность, соответствие
working fluid – рабочее тело
(жидкость)
Task 4. Translate the words into Russian. Mind suffixes and prefixes.
To absorb – absorber, to oxidize – oxidizer, to compose – to decompose, suitable –
suitability, cooled – uncooled, to cool – coolant, to combust – combustion – combustor
– precombustor, simple – simplicity, efficient – efficiently, successful – successfully, to
expand – expander, charge – discharge, burner – preburner, symmetrical -
unsymmetrical
Task 5. Read and translate the following international words.
Turbine, inert, mass, energy, cycle, generator, fluid, impulse, optimum,
optimization, criterion, maximum, peroxide, catalyst, segment, modification,
solenoid, kerosene, dimethyl hydrazine, tetroxide
Task 6. Translate the sentences into Russian using the terms from Task 3.
1. An engine cycle for turbopump-fed engines describes the specific propellant
flow paths through the major engine components, the method of providing the hot gas
to one or more turbines, and the method of handling the turbine exhaust gases.
2. In closed cycles the turbine exhaust gas is expanded through the full pressure
77
ratio of the main thrust chamber nozzle, thus giving a little more performance than
the open cycles, where these exhaust gases expand only through a relatively small
pressure ratio.
3. The gas generator mixture ratio is usually fuel or oxidizer rich so that the gas
temperatures are low enough to allow the use of uncooled turbine blades and
uncooled nozzle exit segments.
4. The expander cycle works best with vaporized cryogenic hydrogen as the
coolant for the thrust chamber, because it is an excellent heat absorber and does not
decompose.
5. Typically, the turbine exhaust gas is discharged overboard through one or two
separate small low-area-ratio nozzles (at relatively low specific impulse).
Task 7. Read the following text carefully paying attention to the words in bold
type. Try to understand the subject matter of the text and be ready to answer the
following questions.
TEXT
TURBOPUMP FEED SYSTEMS AND ENGINE CYCLES
(Part 1)
In a rocket engine with a turbopump feed system the propellants are pressurized
by means of pumps, which in turn are driven by turbines. These turbines derive their
power from the expansion of hot gases. Engines with turbopumps are preferred for
booster and sustainer stages of space launch vehicles, long-range missiles, and in the
past for aircraft performance augmentation. They are usually lighter than other types
for these high thrust, long duration applications. The inert hardware mass of the
rocket engine (without tanks) is essentially independent of duration. For aircraft
performance augmentation the rocket pump can be driven directly by the jet engine.
From the turbopump feed system options the designer can select the most suitable
concept for a particular application.
An engine cycle for turbopump-fed engines describes the specific propellant flow
paths through the major engine components, the method of providing the hot gas to
one or more turbines, and the method of handling the turbine exhaust gases.
There are open cycles and closed cycles. Open denotes that the working fluid
exhausting from the turbine is discharged overboard, after having been expanded in a
nozzle of its own, or discharged into the nozzle of the thrust chamber at a point in the
expanding section far downstream of the nozzle throat. In closed cycles all the
working fluid from the turbine is injected into the engine combustion chamber to
make the most efficient use of its remaining energy. In closed cycles the turbine
exhaust gas is expanded through the full pressure ratio of the main thrust chamber
nozzle, thus giving a little more performance than the open cycles, where these
exhaust gases expand only through a relatively small pressure ratio. The overall
engine performance difference is typically between 1 and 8% of specific impulse and
78
this is reflected in even larger differences in vehicle performance.
The gas generator cycle and the staged combustion cycle can use most of the
common liquid propellants. The expander cycle works best with vaporized cryogenic
hydrogen as the coolant for the thrust chamber, because it is an excellent heat
absorber and does not decompose.
An arrangement with the fuel and oxidizer pump driven by the same turbine is
also feasible and sometimes reduces the hardware mass, volume, and cost. The ‘best’
cycle has to be selected on the basis of the mission, the suitability of existing
engines, and the criteria established for the particular vehicle.
There is an optimum chamber pressure and an optimum mixture ratio for each
application, engine cycle, or optimization criterion, such as maximum range, lowest
cost, or highest payload.
In the gas generator cycle the turbine inlet gas comes from a separate gas
generator. Its propellants can be supplied from separate propellant tanks or can be
bled off the main propellant feed system. This cycle is relatively simple; the pressures
in the liquid pipes and pumps are relatively low (which reduces inert engine mass). It
has less engine-specific impulse than an expander cycle or a staged combustion cycle.
The pressure ratio across the turbine is relatively high, but the turbine or gas
generator flow is small (1 to 4% of total propellant flow) if compared to closed
cycles. Some early engines used a separate monopropellant for creating the generator
gas. The German V-2 missile engine used hydrogen peroxide, which was
decomposed by a catalyst. Typically, the turbine exhaust gas is discharged overboard
through one or two separate small low-area-ratio nozzles (at relatively low specific
impulse). Alternatively, this turbine exhaust can be aspirated into the main flow
through openings in the diverging nozzle section. This gas then protects the walls
near the nozzle exit from high temperatures. Both methods can provide a small
amount of additional thrust. The gas generator mixture ratio is usually fuel rich (in
some engine it is oxidizer rich) so that the gas temperatures are low enough (typically
900 to 1350 K) to allow the use of uncooled turbine blades and uncooled nozzle exit
segments. The RS-68 rocket engine has a simple gas generator cycle. This engine is
the largest liquid hydrogen/liquid oxygen rocket engine built to date. With a gas
generator cycle the specific impulse of the thrust chamber by itself is always a little
higher than that of the engine and the thrust of the thrust chamber is always slightly
lower than that of the engine.
(Sutton, George P. & Biblarz, Oscar Rocket Propulsion Elements: an introduction to
the engineering of rockets)
Task 8. Find in the text the English equivalents for the following words and word
combinations.
Турбонасосная система подачи топлива, расширение, стартовый ускоритель,
ракетный двигатель маршевой ступени, космическая ракета-носитель, ракеты
дальнего действия, характеристики летательного аппарата, тяга, масса
аппарата, реактивный двигатель, цикл двигателя, расчетная траектория
топливного потока, отработавшие в турбине газы, сопло камеры сгорания,
79
горло сопла, рабочее тело, степень расширения, удельный импульс, хладагент,
turbopump-fed engines, the nozzle exit, monopropellant, coolant, the expansion, the
turbine inlet gas, the expander cycle, the gas generator cycle, the thrust chamber,
open cycle, the propellants, engines with turbopumps, engine performance difference,
the engine
An engine cycle for turbopump-fed
engines describes …
into the engine combustion chamber to
make the most efficient use of its
remaining energy.
теплопоглотитель, разлагаться на составные элементы, объем, оптимальное
соотношение компонентов топлива, полезная нагрузка, однокомпонентное
ракетное топливо, сопла с малой степенью уширения, расширяющаяся часть
сопла, избыток горючего, избыток окислителя, рабочие лопатки турбины.
Task 9. Fill in the gaps with appropriate words from the box.
1. The turbines derive their power from ___________ of hot gases.
2. _________ denotes that the working fluid exhausting from the turbine is
discharged overboard.
3. Some early engines used a separate ___________ for creating the generator
gas.
4. __________ are usually lighter than other types for these high thrust, long
duration applications.
5. The turbine exhaust gas protects the walls near __________from high
temperatures.
6. The overall ____________ is typically between 1 and 8% of specific impulse
and this is reflected in even larger differences in vehicle performance.
7. In the gas generator cycle ___________ comes from a separate gas generator.
8. In a rocket engine with a turbopump feed system ___________ are pressurized
by means of pumps, which in turn are driven by turbines.
9. An engine cycle for __________describes the specific propellant flow paths
through the major engine components.
10. ___________ and the staged combustion cycle can use most of the
common liquid propellants.
11. ___________ works best with vaporized cryogenic hydrogen as the
__________ for the thrust chamber.
12. With a gas generator cycle the specific impulse of ___________ by itself
is always a little higher than that of the engine and the thrust of the thrust chamber is
always slightly lower than that of___________.
Task 10. Complete the sentences with appropriate endings.
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