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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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8. После израсходования компонентов ракетного топлива полностью
1. to feature
2. thruster selection system
3. safety device
4. automatic controls
5. sensor/gauge
6. manual command override
7. pressure regulator
8. redundancy
9. to run
10. propellant
11. to feed
12. emergency mode
13. compartmented
14. antislosh baffle
15. antivortex baffle
16. sump
17. surface tension
18. retention device
19. propellant load
20. acceleration environment
21. leak/leakage
1. избыточность
2. аварийный режим
3. датчик
4. спрямляющее кольцо,
антизавихритель
5. устройство стабилизации
6. компонент ракетного топлива
7. гаситель колебаний топлива
8. поверхностное натяжение
9. характеризоваться
10. условия воздействия ускорений
11. утечка
12. автоматические регуляторы
13. влага
14. система выбора двигателя
управления
15. сопло
16. запас топлива
17. переход на ручное управление по
командам
18. разделенный на отсеки
вытесняющий газ высокого давления используется для продувки и очистки
топливопроводов от остаточного количества жидкого компонента ракетного
топлива.
9. Использование однокомпонентного ракетного топлива упрощает
вытеснительную систему подачи топлива за счет сокращения количества
трубопроводов, клапанов и баков.
10. Датчики, находящиеся в каждом баке, позволяют определить
количество оставшегося ракетного топлива, а также показать наличие утечки.
11. Для предотвращения замерзания топлива и превращения влаги в
лед около топливных клапанов, отдельных топливопроводов и инжекторов
устанавливаются электрические нагреватели.
12. Поскольку электрические соединительные провода, ведущие к
топливным клапанам, наматываются на камеру сгорания и сопло, выгорание
топлива приведет к быстрому расплавлению провода и прекращению подачи
электроэнергии на топливные клапаны, что приведет их в подпружиненное
закрытое положение и перекроет подачу компонентов ракетного топлива.
Task 14. Find the Russian equivalents for the English terms.
51
22. propellant valve actuator
23. heater
24. moisture
25. reliability
26. self-shutoff device
27. shutdown
28. to burn
29. nozzle
30. burnout
19. запускать
20. подавать (топливо)
21. устройство обеспечения
безопасности
22. резервуар для хранения
23. регулятор давления
24. гореть
25. приводной механизм топливного
клапана
26. выгорание топлива
27. надежность
28. выключение/отсечка двигателя
29. устройство для самостоятельного
отключения двигателя
30. нагреватель
Task 15. Look through the texts (Task 7, 11) and find key sentences in each
paragraph.
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.
GAS PRESSURE FEED SYSTEMS
The majority of pressurized feed systems use a pressure regulator to maintain the
propellant tank pressure and thus also the thrust at constant values. The required mass
of pressurizing gas can be significantly reduced by a blow-down system with a “tail-
off” pressure decay. The propellants are expelled by the expansion of the gas already
in the enlarged propellant tanks. The tank pressure and the chamber pressure decrease
or progressively decay during this adiabatic expansion period.
Some pressure feed systems can be prefilled with propellant and pressurizing
agent at the factory and stored in readiness for operation. Compared to a solid
propellant rocket unit, these storable prepackaged liquid propellant pressurized feed
systems offer advantages in long-term storability and resistance to transportation
vibration or shock.
The thrust level of a rocket propulsion system with a pressurized gas feed system
is determined by the magnitude of the propellant flow which, in turn, is determined
by the gas pressure regulator setting. The propellant mixture ratio in this type of feed
system is controlled by the hydraulic resistance of the liquid propellant lines, cooling
jacket, and injector, and can usually be adjusted by means of variable or
interchangeable restrictors.
(Sutton, George P. & Biblarz, Oscar Rocket Propulsion Elements: an introduction to
(Part III)
the engineering of rockets)
52
Task 19. Choose the right variant to fill in the gap.
1. The majority of pressurized feed systems use ___________ to maintain the
propellant tank pressure and thus also the thrust at____________.
a) a pressure gauge, constant values
b) a pressure regulator, constant values
c) a pressure regulator, running values
2. The required __________of pressurizing gas can be significantly reduced by a
blow-down system with a “tail-off” pressure decay.
a) mass
b) amount
c) volume
3. The tank pressure and the chamber pressure __________or progressively decay
during this __________ period.
a) increase, adiabatic recompression
b) increase, adiabatic cooling
c) decrease, adiabatic expansion
4. Some pressure feed systems can be prefilled with ____________ at the factory
and stored in readiness for operation.
a) propellant and pressurizing agent
b) oxidizer and fuel
c) propellant and oxidizer
5. __________ of a rocket propulsion system with a pressurized gas feed system
is determined by the magnitude of the propellant flow.
a) The thrust development
b) The thrust level
c) The thrust value
6. The propellant mixture ratio is controlled by ___________ of the liquid
propellant lines, cooling jacket, and injector.
a) the hydraulic resistance
b) the hydraulic pressure
c) the hydraulic force
Task 20. Collect all the possible supplementary information on the theme of Unit
5 and present it to your groupmates.
53
UNIT 6. Propellant Tanks
Forms
Transitive verbs
Intransitive verbs
Active
Passive
Active
Present Participle
inviting
being invited
going
Past Participle
invited
gone
Perfect Participle
having invited
having been invited
having gone
The function of the Participle
Example
Predicative
Cryogenic tanks are usually thermally
insulated.
Attribute
These frozen particles would plug up
injection holes.
Adverbial
Porous external insulation layers have to
be sealed to prevent moisture from being
condensed inside the insulation layer.
TEXT: PROPELLANT TANKS
Grammar: The Participle
Task 1. Study the forms and the functions of the Participle in the English
sentences and translate them into Russian.
Task 2. Find the Participle in the English sentences and translate them into
Russian. Pay attention to the ways it is expressed in Russian sentences.
1. The extra volume of gas above the propellant in sealed tanks is called ullage.
2. Depending on the storage temperature range, the propellants’ coefficient of
thermal expansion, and the particular application, the ullage volume is usually
between 3 and 10% of the tank volume.
3. The expulsion efficiency of a tank and/or propellant piping system is the
amount of propellant expelled or available divided by the total amount of propellant
initially present.
4. This residual propellant is not available for combustion and must be treated as
inert mass, causing the vehicle mass ratio to decrease slightly.
5. The optimum shape of a propellant tank is spherical, because for a given
volume it results in a tank with the least weight.
6. Frozen particles would prevent valves from being fully closed.
7. If the tank or any segment of piping containing low-temperature cryogenic
liquid is sealed for an extended period of time, heat from ambient-temperature
hardware will result in evaporation.
54
Task 3. Study the following words and word combinations and learn them by heart.
alloy steel – легированная сталь
to arrange – располагать,
устанавливать
to be at a premium – зд. иметь
первостепенное значение
bulk temperature – средняя
температура массы
center of gravity – центр тяжести
design – конструкция
to dissolve – растворять
to exercise – осуществлять
expulsion efficiency – полнота
(коэффициент) вытеснения
fiber-reinforced –армированный
волокном
fitting – соединение
groove – вырез, канавка
inner liner – внутренняя оболочка,
облицовка
liquid bipropellant – жидкое
двухкомпонентное ракетное топливо
mass ratio – относительный вес
топлива
monopropellant – однокомпонентное
(унитарное) ракетное топливо
to pressurize – создавать наддув
sealed tank – герметизированный бак
storage – хранение
stressed – нагруженный, напряженный
surface tension – поверхностное
натяжение
tap – штуцер
thermal expansion – температурное
расширение
ullage – газовая подушка
wing – крыло
Task 4. Translate the words into Russian. Mind suffixes and prefixes.
Available – unavailable, to locate – location, to oxidize – oxidizer, pressure – to
pressurize, high – highly, original – originally, gas – gaseous, to store – storage, to expand –
expansion, initial – initially, minimum – minimize, to equip – equipment, fortunate –
fortunately – unfortunately, regular – irregular.
Task 5. Read and translate the following international words.
Aluminum, titanium, plastics, metal, pore, thermal, accumulation, product, reaction,
temperature, coefficient, efficiency, inert, mass, spherical, integral, fuselage, cylindrical,
ellipse, condensation, period.
Task 6. Translate the sentences into Russian using the terms from Task 3.
1. There are also one or more high-pressure gas tanks, the gas being used to
pressurize the propellant tanks.
2. Because the propellant tank has to fly, its mass is at a premium and the tank
material is therefore highly stressed.
3. Once propellant is loaded into a tank, the ullage volume (and, if it is sealed also
its pressure) will change as the bulk temperature of the propellant varies.
4. The expulsion efficiency of a tank and/or propellant piping system is the
55
amount of propellant expelled or available divided by the total amount of propellant
initially present.
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.
1. What is the difference between propellant storage systems in liquid
bipropellant and monopropellant rocket engine systems?
2. What can the tank design be used for?
3. What is the reason for the propellant tank mass to be at a premium and for the
tank material to be highly stressed?
4. What are propellant tanks made of?
5. What does the term ullage mean?
6. What does ullage volume depend on?
7. How much space does ullage volume occupy?
8. What does the expulsion efficiency of a tank and/or propellant piping system
mean?
9. Why is it necessary to minimize the residual propellant in the design of tanks
and piping systems?
10. What are advantages and shortcomings of the spherical shape of a
propellant tank?
Propellant Tanks
(Part I)
In liquid bipropellant rocket engine systems propellants are stored in one or
more oxidizer tanks and one or more fuel tanks; monopropellant rocket engine
systems have only one set of propellant tanks. There are also one or more highpressure gas tanks, the gas being used to pressurize the propellant tanks. Tanks can
be arranged in a variety of ways, and the tank design can be used to exercise some
control over the change in the location of the vehicle’s center of gravity. Because the
propellant tank has to fly, its mass is at a premium and the tank material is therefore
highly stressed. Common tank materials are aluminum, stainless steel, titanium,
alloy steel, and fiber-reinforced plastics with an impervious thin inner liner of
metal to prevent leakage through the pores of the fiber-reinforced walls.
The extra volume of gas above the propellant in sealed tanks is called ullage. It is
necessary space that allows for thermal expansion of the propellant liquids, for the
accumulation of gases that were originally dissolved in the propellant, or for gaseous
products from slow reactions within the propellant during storage. Depending on the
storage temperature range, the propellants’ coefficient of thermal expansion, and the
particular application, the ullage volume is usually between 3 and 10% of the tank
volume. Once propellant is loaded into a tank, the ullage volume (and, if it is sealed,
also its pressure) will change as the bulk temperature of the propellant varies.
56
The expulsion efficiency of a tank and/or propellant piping system is the amount
the storage temperature, reaction control engine systems, thermal expansion, the
expulsion efficiency, the tank design, the extra volume, cylindrical, the propellant
tank, spherical, the fiber-reinforced walls
of propellant expelled or available divided by the total amount of propellant initially
present. Typical values are 97 to 99.7%. The losses are unavailable propellants that
are trapped in grooves or corners of pipes, fittings, and valves, are wetting the walls,
retained by surface tension, or caught in instrument taps. This residual propellant is
not available for combustion and must be treated as inert mass, causing the vehicle
mass ratio to decrease slightly. In the design of tanks and piping systems, an effort is
made to minimize the residual propellant.
The optimum shape of a propellant tank (and also a gas pressurizing tank) is
spherical, because for a given volume it results in a tank with the least weight. Small
spherical tanks are often used with reaction control engine systems, where they can
be packaged with other vehicle equipment. Unfortunately, the larger spheres, which
are needed for the principal propulsion systems, are not very efficient for using the
space in a vehicle. These larger tanks are often made integral with the vehicle
fuselage or wing. Most are cylindrical with half ellipses at the ends, but they can be
irregular in shape.
(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.
Баки окислителя, баки газа под высоким давлением, создавать наддув, центр
тяжести, высоко нагруженный, пластмасса, армированная волокном,
легированная сталь, непроницаемый, внутренняя оболочка, утечка,
герметизированные баки, тепловое расширение, средняя температура ракетного
топлива, коэффициент вытеснения, недоступные компоненты ракетного
топлива, канавки, соединения, поверхностное натяжение, приборные штуцеры,
невыработанное ракетное топливо, двигатель системы реактивного управления.
Task 9. Fill in the gaps with appropriate words from the box.
1. Tanks can be arranged in a variety of ways, and ___________can be used to
exercise some control over the change in the location of the vehicle’s center of
gravity.
2. Because ____________has to fly, its mass is at a premium and the tank
material is therefore highly stressed.
3. Common tank materials are aluminum, stainless steel, titanium, alloy steel, and
fiber-reinforced plastics with an impervious thin inner liner of metal to prevent
leakage through the pores of_____________.
57
4. __________of gas above the propellant in sealed tanks is called ullage.
The tank design can be used to exercise
…
is called ullage.
Because the propellant tank has to fly, …
that are trapped in grooves or corners of
pipes, fittings, and valves, are wetting the
walls, retained by surface tension, or
caught in instrument taps.
The extra volume of gas above the
propellant in sealed tanks …
will change as the bulk temperature of the
propellant varies.
Once propellant is loaded into a tank, the
ullage volume …
some control over the change in the
location of the vehicle’s center of gravity.
The losses are unavailable propellants …
because for a given volume it results in a
tank with the least weight.
The optimum shape of a propellant tank
is spherical, …
its mass is at a premium and the tank
material is therefore highly stressed.
5. It is necessary space that allows for __________of the propellant liquids, for
the accumulation of gases that were originally dissolved in the propellant, or for
gaseous products from slow reactions within the propellant during storage.
6. Depending on __________ range, the propellants’ coefficient of thermal
expansion, and the particular application, the ullage volume is usually between 3 and
10% of the tank volume.
7. ___________of a tank and/or propellant piping system is the amount of
propellant expelled or available divided by the total amount of propellant initially
present.
8. The optimum shape of a propellant tank (and also a gas pressurizing tank)
is__________, because for a given volume it results in a tank with the least weight.
9. Small spherical tanks are often used with___________, where they can be
packaged with other vehicle equipment.
10. Most tanks are ____________with half ellipses at the ends, but they can
be irregular in shape.
Task 10. Complete the sentences with appropriate endings.
Task 11. Read the following text and try to understand its subject matter.
Translate the text into Russian. Use the dictionary if necessary.
Cryogenic propellants cool the tank wall temperature far below the ambient air
temperature. This causes condensation of moisture on the outside of the tank and
usually also formation of ice during the period prior to launch. The ice is undesirable,
because it increases the vehicle inert mass and can cause valves to malfunction. Also,
Propellant Tanks
(Part II)
58
as pieces of ice are shaken off or break off during the initial flight, these pieces can
damage the vehicle; for example, the ice from the Shuttle's cryogenic tank can hit the
orbiter vehicle.
For an extended storage period, cryogenic tanks are usually thermally insulated;
porous external insulation layers have to be sealed to prevent moisture from being
condensed inside the insulation layer. With liquid hydrogen it is possible to liquify or
solidify the ambient air on the outside of the fuel tank. Even with heavy insulation
and low-conductivity structural tank supports, it is not possible to prevent the
continuous evaporation of the cryogenic fluid. Even with good thermal insulation, all
cryogenic propellants evaporate slowly during storage and therefore cannot be kept in
a vehicle for more than a week without refilling of the tanks. For vehicles that need to
be stored or to operate for longer periods, a storable propellant combination must be
used.
Prior to loading very cold cryogenic propellant into a flight tank, it is necessary to
remove or evacuate the air to avoid forming solid air particles or condensing any
moisture as ice. These frozen particles would plug up injection holes, cause valves to
freeze shut, or prevent valves from being fully closed. Tanks, piping, and valves need
to be chilled or cooled down before they can contain cryogenic liquid without
excessive bubbling. This is usually done by letting the initial amount of cryogenic
liquid absorb the heat from the relatively warm hardware. This initial propellant is
vaporized and vented through appropriate vent valves.
If the tank or any segment of piping containing low-temperature cryogenic liquid
is sealed for an extended period of time, heat from ambient-temperature hardware
will result in evaporation and this will greatly raise the pressure until it exceeds the
strength of the container. This self-pressurization will cause a failure, usually a major
leak or even an explosion. All cryogenic tanks and piping systems are therefore
vented during storage on the launch pad, equipped with pressure safety devices (such
as burst diaphragms or relief valves), and the evaporated propellant is allowed to
escape from its container. For long-term storage of cryogenic propellants in space
vacuum (or on the ground) some form of a powered refrigeration system is needed to
recondense the vapors and minimize evaporation losses. The tanks are refilled or
topped off just before launch to replace the evaporated vented propellant. When the
tank is pressurized, just before launch, the boiling point is usually raised slightly and
the cryogenic liquid can usually absorb the heat transferred to it during the several
minutes of rocket firing.
There are several categories of tanks in liquid propellant propulsion systems:
1. For pressurized feed systems the propellant tanks typically operate at an
average pressure between 1.3 and 9 MPa or about 200 to 1800 lbf/in2. These tanks
have thick walls and are heavy.
2. For high-pressure gas (used to expel the propellants) the tank pressures are
much higher, typically between 6.9 and 69 MPa or 1000 to 10,000 lbf/ in2. These
tanks are usually spherical for minimum inert mass. Several small spherical tanks can
be connected together and then they are relatively easy to place within the confined
space of a vehicle.
59
3. For turbopump feed systems it is necessary to pressurize the propellant tanks
slightly (to suppress pump cavitation) to average values of between 0.07 and 0.34
MPa or 10 to 50 lbf/in2. These low pressures allow thin tank walls, and therefore
turbopump feed systems have relatively low tank weights.
Liquid propellant tanks can be difficult to empty under side accelerations, zero-g,
or negative-g conditions during flight. Special devices and special types of tanks are
needed to operate under these conditions.
The oscillations and side accelerations of vehicles in flight can cause sloshing of
the liquid in the tank, very similar to a glass of water that is being jiggled. In an
antiaircraft missile, for example, the side accelerations can be large and can initiate
sloshing. When the tank is partly empty, sloshing can uncover the tank outlet and
allow gas bubbles to enter into the propellant discharge line. These bubbles can cause
major combustion problems in the thrust chambers; the aspirating of bubbles or the
uncovering of tank outlets by liquids therefore needs to be avoided. Sloshing also
causes shifts in the vehicle's center of gravity and makes flight control difficult.
Vortexing can also allow gas to enter the tank outlet pipe; this phenomenon is
similar to the Coriolis force effects in bath tubs being emptied and can be augmented
if the vehicle spins or rotates in fight. Typically, a series of internal baffles is often
used to reduce the magnitude of sloshing and vortexing in tanks with modest side
accelerations. A positive expulsion mechanism can prevent gas from entering the
propellant piping under multidirectional major accelerations or spinning (centrifugal)
acceleration. Both the vortexing and sloshing can greatly increase the unavailable or
residual propellant, and thus cause a reduction in vehicle performance.
(Sutton, George P. & Biblarz, Oscar Rocket Propulsion Elements: an introduction to
the engineering of rockets)
Task 12. Answer the questions and use them as a plan for retelling the text.
1. What does the use of cryogenic propellants cause?
2. Why is formation of ice during the period prior to launch undesirable?
3. What should be done with cryogenic tanks in case of extended storage period?
4. Why is it impossible to keep cryogenic propellants in a vehicle for more than a
week without refilling of the tanks.
5. Why is it necessary to remove the air prior to loading very cold cryogenic
propellant?
6. What is the reason for chilling tanks, piping and valves and how is it
performed?
7. Why are all cryogenic tanks and piping systems vented during storage on the
launch pad, equipped with pressure safety devices?
8. How many categories of tanks are there in liquid propellant propulsion
systems?
9. What are the main features of these tanks?
10. What can the oscillations and side accelerations of vehicles in flight
cause?
60
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