PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
LEARNING
MODULE 07:
Performance and Thrust
Augmentation
POWERPLANT II – GAS TURBINE
ENGINE
Prepared by:
AERO FACULTY
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
TABLE OF CONTENTS
TOPIC
PAGE
Water Injection Systems
4
Water - Methanol Injection
7
Methods Of Injection
8
Compressor Inlet Injection
8
Combustion Chamber Injection
10
Thrust Augmentation By Afterburning
12
Operations Of Afterburning
15
Construction – Afterburning
17
Afterburning Control System
21
Thrust Increase – Afterburning
25
Fuel Consumption – Afterburning
26
ACTIVITY
PAGE
Research Paper
29
Activity 1
29
HONESTY CLAUSE
As an institution of higher learning, students are expected to display highest degree
of honesty and professionalism in their class work, requirements, and activities; thus,
in no case that cheating—or any form of it, may it be plagiarism, copying other
students' works, and fabrication of materials—shall be tolerated.
The College assumes as a simple and minimal preferred of habits in academic
matters that students be truthful and that they publish for deposit solely the
merchandise of their personal efforts.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
LEARNING OUTCOMES
Course Learning Outcomes [CLO]
Module Learning Outcomes [MLO]
CLO 2. Learn the design principles and
operation of gas turbine engines through
summarization of the process of
producing thrust.
CLO 4. To be able to identify and explain
the different sections of a gas turbine
engine by defining the functions of each
sections of the engine.
CLO 5. To be able to classify and explain
each type of power plant systems
through illustrative activities.
CLO 7. To be able to define and explain
principles of gas turbine operation
through summarization of the process of
producing thrust.
MLO 1. Explain the role of afterburners
and their impact in the performance of
the aircraft through illustrative activities.
MLO 2. Identify different types of
afterburners and thrust augmentation
methods used in a gas turbine engine
through illustrative activities.
Topic Learning Outcomes [TLO]
TLO 1. Familiarize with the operation of
the afterburners of a gas turbine engine
by outlining the operation of the fuel
system inside the engine.
TLO 2. Identify the different types of
afterburners used in different types of
gas turbine engine through illustrative
activities.
TLO 3. Describe and explain the
operating principles of afterburner and
when this is being operated during flight.
TLO 4. Understand the operating
principle of a water/methanol injection
system as another method for thrust
augmentation and explain its purpose
and the different point of injection.
TLO 5. Explain how water/methanol
injection system is activated.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
PERFORMANCE AUGMENTATION
WATER INJECTION SYSTEMS
The maximum power output of a gas turbine engine depends to a large extent upon
the density or weight of the airflow passing through the engine. There is, the refore, a
reduction in thrust or shaft horsepower as the atmospheric pressure decreases with
altitude, and/or the ambient air temperature increases.
Under these conditions, the power output can be restored or, in some instances,
boosted for take-off by cooling the airflow with water or water/methanol mixture
(coolant). When methanol is added to the water it gives anti-freezing properties and
also provides an additional source of fuel.
Supplemental Video on Performance and Thrust Augmentation:
https://youtu.be/6Z0CDZ_9cWo
In conditions of high altitude and/or high temperature the use of water injection can
restore the thrust of a turbo-jet engine and boost the output of a turbo-prop engine.
The water injection system is typically activated by moving the throttle to the take-off
position.
The power output of a gas turbine engine depends to a large extent upon the mass of
air flowing through it. In conditions of high altitude and/or high temperature, the
density, and therefore the mass of the airflow through the engine decreases, causing
a reduction of thrust or shaft horse power.
To restore, or with some types of engine, boost, the power output of that engine, the
airflow can be cooled with water.
Figure 1 shows a thrust restoration curve for a typical turbojet engine, while Figure
2 shows a power restoration and boost curve for a turboprop engine.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 1 - A thrust restoration curve for a typical turbojet engine.
Note that while in Figure 1, the engine power does not increase above its flat rated
100% power, which is controlled by the power limiter circuit. In Figure 2, the engine
power is boosted by up to 15%.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 2 - A thrust restoration and boost curve for a typical turboprop engine.
In the former case, the turbojet engine, although the mass of the airflow can be
increased with relatively few problems by increasing the compressor speed the
maximum compressor outlet pressure (P3max), must be limited to prevent the engine
carcass splitting under excessive stress.
As in the latter case, that of the turboprop engine, if the water is injected into the
combustion chamber, which is by far the most popular method of water injection, the
mass flow through the turbine is increased relative to that flowing through the
compressor.
This increase in mass flow through the turbine is not used to increase compressor
RPM, and thereby increase P3 pressure, but is absorbed by coarsening the propeller
pitch to increase the mass of air being thrust rearwards, while maintaining the engine
speed at no more than the normal maximum (increasing SHP).
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
WATER - METHANOL INJECTION
A pure water injection system does have some drawbacks, not least because the
water must all be used up on take-off if it is not to freeze in the tanks as the aircraft
climbs to altitude.
It would be logical to require an injection fluid that did not freeze, thus methanol is
added to the water. This serves primarily as an anti-freeze, there is however an
additional bonus achieved by using methanol. By injecting coolant into the combustion
chamber, the TGT (turbine gas temperature), is lowered dramatically which somewhat
lowers the power available (remember that the turbojet is a heat engine).
Methanol, being an alcohol fuel, burns, and adds to the temperature of the gases,
raising the TGT back to its original level.
In order to regulate the amount of heat added, the quantity of water methanol injected
into the engine must be carefully regulated, this is done by a water methanol control
system. The proportion of methanol added to the water must also be carefully
controlled, a ratio of 40% methanol to 60% water (by volume) ensures that the TGT
limits should never be exceeded during use of the water methanol system.
The amount of water which is carried can be large, the Boeing 707 and the DC-8 carry
approximately 300 gallons of water injection fluid per engine which must all be used
up in a three minute take off and climb.
This equates to a water flow rate of 100 gallons per minute. The fuel flow through each
engine at this time is 9,000 lbs/hour (22 gallons/minute). This gives a water flow to fuel
flow ratio of 4.5:1.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
METHODS OF INJECTION
Some centrifugal compressor engines, and some small American designed axial flow
compressor engines, injected the water into the engine intake or also known as the
compressor inlet. Unfortunately, water distribution was not of the best and the
quantity of water had to be limited so as not to cause an engine flame out.
As was mentioned in the previous paragraph, injection of water into the combustion
chamber increases the mass flow through the turbine relative to that through the
compressor. Because the turbine has no extra work to do to obtain this increase mass
flow, there is a related decrease in the pressure drop across it.
This results in an increase in the amount of power available, either to drive the
propeller through a free turbine, or as an increase in the jet pipe pressure.
COMPRESSOR INLET INJECTION
The compressor inlet injection system as shown in the figure below is a typical system
for a turbo-propeller engine. When the injection system is switched on, water/methanol
mixture is pumped from an aircraft mounted tank to a control unit.
The control unit meters the flow of mixture to the compressor inlet through a metering
valve that is operated by a servo piston. The servo system uses engine oil as an
operating medium, and a servo valve regulates the supply of oil. The degree of servo
valve opening is set by a control system that is sensitive to propeller shaft torque oil
pressure and to atmospheric air pressure acting on a capsule assembly.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 3 - A typical compressor inlet injection system.
The control unit high pressure oil cock control lever is interconnected to the throttle
control system in such a manner that, until the throttle is moved towards the take-off
position, the oil cock remains closed, and thus the metering valve remains closed,
preventing any mixture flowing to the compressor inlet.
Movement of the throttle control to the take-off position opens the oil cock, and the oil
pressure passes through the servo valve to open the metering valve by means of the
servo piston.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
COMBUSTION CHAMBER INJECTION
The combustion chamber injection system shown in the figure shown below is a typical
system for a turbojet engine. The coolant flows from an aircraft-mounted tank to an
air-driven turbine pump that delivers it to a water flow sensing unit. The water passes
from the sensing unit to each fuel spray nozzle and is sprayed from two jets onto the
flame tube swirl vanes, thus cooling the air passing into the combustion zone.
Figure 4 - A typical combustion chamber injection system.
The water pressure between the sensing unit and the discharge jets is sensed by the
fuel control system, which automatically resets the engine speed governor to give a
higher maximum engine speed.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
The water flow sensing unit opens only when the correct pressure difference is
obtained between compressor delivery air pressure and water pressure. The system
is brought into operation when the engine throttle lever is moved to the take-off
position, causing micro switches to operate and select the air supply for the turbine
pump.
The sensing unit also forms a non-return valve to prevent air pressure feeding back
from the discharge jets and provides for the operation of an indicator light to show
when water is flowing.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
THRUST AUGMENTATION BY AFTERBURNING
Thrust augmentation by afterburning (reheat) makes use of the unburnt oxygen in the
exhaust to release more heat energy by burning more fuel between the turbine and
the propelling nozzle. Afterburning is used to improve takeoff and climb or combat
performance, mainly restricted to military aircraft.
Figure 5 - Principle of afterburning.
The one notable exception is Concorde, currently the only supersonic passenger
carrying aircraft using four low by-pass ratio turbojets with afterburners.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 6 – A Concorde during takeoff with afterburners being operated.
Fuel is introduced into the jet pipe through discharge nozzles centrally disposed
around the axis of flow to enable some of the relatively cooler turbine discharge gas
to flow along the jet pipe walls to aid cooling as the afterburner flame temperature may
be in excess of 1700°C.
An afterburning jet pipe will have a variable area propelling nozzle, closed, to
provide for non-afterburning operation and open, to allow for an increased volume of
gas during afterburning operation.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 7 - A variable area propelling nozzle.
Control of the nozzle is automatic with the selection of afterburner which is typically
initiated by moving the throttle lever through a detent or 'gate'.
The velocity of the gas stream from the turbine is diffused before entering the
afterburner section to reduce the velocity sufficiently to enable the afterburner flame
to remain stable.
When selected an atomized fuel spray is introduced into the jet pipe through the
burners and ignited by an igniter plug or a hot streak of flame from the combustion
chamber. Once combustion is established the gas temperature increases and the
expanding gas accelerates through the open propelling nozzle providing additional
thrust.
As can be imagined the fuel consumption goes up dramatically so use of the
afterburner is normally limited to short periods.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
OPERATIONS OF AFTERBURNING
The gas stream from the engine turbine enters the jet pipe at a velocity of 750 to 1,200
feet per second, but as this velocity is far too high for a stable flame to be maintained,
the flow is diffused before it enters the afterburner combustion zone, i.e. the flow
velocity is reduced and the pressure is increased.
However, as the speed of burning kerosene at normal mixture ratios is only a few feet
per second, any fuel lit even in the diffused air stream would be blown away. A form
of flame stabilizer (vapor gutter) is, therefore, located downstream of the fuel burners
to provide a region in which turbulent eddies are formed to assist combustion and
where the local gas velocity is further reduced to a figure at which flame stabilization
occurs whilst combustion is in operation.
An atomized fuel spray is fed into the jet pipe through a number of burners, which are
so arranged as to distribute the fuel evenly over the flame area.
Combustion is then initiated by a catalytic igniter, which creates a flame as a result of
the chemical reaction of the fuel/air mixture being sprayed on to a platinum-based
element, by an igniter plug adjacent to the burner, or by a hot streak of flame that
originates in the engine combustion chamber this latter method is known as 'hot-shot'
ignition.
Once combustion is initiated, the gas temperature increases and the expanding gases
accelerate through the enlarged area propelling nozzle to provide the additional thrust.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 8 - Methods of afterburning ignition.
In view of the high temperature of the gases entering the jet pipe from the turbine, it
might be assumed that the mixture would ignite spontaneously. This is not so, for
although cool flames form at temperatures up to 700 degrees Celsius, combustion will
not take place below 800 degrees Celsius.
If however, the conditions were such that spontaneous ignition could be effected at
sea level, it is unlikely that it could be effected at altitude where the atmospheric
pressure is low. The spark or flame that initiates combustion must be of such intensity
that a light-up can be obtained at considerable altitudes.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
For smooth functioning of the system, a stable flame that will burn steadily over a wide
range of mixture strengths and gas flows is required. The mixture must also be easy
to ignite under all conditions of flight and combustion must be maintained with the
minimum loss of pressure.
CONSTRUCTION – AFTERBURNING
● Burners
The burner system consists of several circular concentric fuel manifolds
supported by struts inside the jet pipe. Fuel is supplied to the manifolds by feed
pipes in the support struts and sprayed into the flame area, between the flame
stabilizers, from holes in the downstream edge of the manifolds.
The flame stabilizers are blunt nosed V-section annular rings located
downstream of the fuel burners. An alternative system includes an additional
segmented fuel manifold mounted within the flame stabilizers. The typical
burner and flame stabilizer shown in the figure below is based on the latter
system.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 9 - A typical afterburning jet pipe equipment.
● Jet Pipe
The afterburning jet pipe is made from a heat resistant nickel alloy and requires
more insulation than the normal jet pipe to prevent the heat of combustion being
transferred to the aircraft structure.
The jet pipe may be of a double skin construction with the outer skin carrying
the flight loads and the inner skin the thermal stresses; a flow of cooling air is
often induced between the inner and outer skins. Provision is also made to
accommodate expansion and contraction, and to prevent gas leaks at the jet
pipe joints.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
A circular heatshield of similar material to the jet pipe is often fitted to the inner
wall of the jet pipe to improve cooling at the rear of the burner section. The
heatshield comprises a number of bands, linked by cooling corrugations, to
form a single skin. The rear of the heatshield is a series of overlapping 'tiles'
riveted to the surrounding skin. The shield also prevents combustion instability
from creating excessive noise and vibration, which in turn would cause rapid
physical deterioration of the afterburner equipment.
● Propelling Nozzle
The propelling nozzle is of similar material and construction as the jet pipe, to
which it is secured as a separate assembly. A two-position propelling nozzle
has two movable eyelids that are operated by actuators, or pneumatic rams, to
give an open or closed position.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 10 - Examples of afterburning jet pipes and propelling nozzles.
A variable-area propelling nozzle has a ring of interlocking flaps that are hinged
to the outer casing and may be enclosed by an outer shroud. The flaps are
actuated by powered rams to the closed position, and by gas loads to the
intermediate or the open positions; control of the flap position is by a control
unit and a pump provides the power to the rams.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
AFTERBURNING CONTROL SYSTEM
It is apparent that two functions, fuel flow and propelling nozzle area, must be
coordinated for satisfactory operation of the afterburner system, These functions are
related by making the nozzle area dependent upon the fuel flow at the burners or vice
versa.
The pilot controls the afterburner fuel flow or the nozzle area in conjunction with a
compressor delivery/jet pipe pressure sensing device (a pressure ratio control unit).
When the afterburner fuel flow is increased, the nozzle area increases when the
afterburner fuel flow decreases, the nozzle area is reduced. The pressure ratio control
unit ensures the pressure ratio across the turbine remains unchanged and that the
engine is unaffected by the operation of afterburning, regardless of the nozzle area
and fuel flow.
Since large fuel flows are required for afterburning, an additional fuel pump is used.
This pump is usually of the centrifugal flow or gear type and is energized automatically
when afterburning is selected. The system is fully automatic and incorporates 'fail safe'
features in the event of an afterburner malfunction. The interconnection between the
control system and afterburner jet pipe is shown diagrammatically in the figure below.
21 | Page
PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 11 - Simplified control system of an aircraft afterburners.
When afterburning is selected, a signal is relayed to the afterburner fuel control unit.
The unit determines the total fuel delivery of the pump and controls the distribution of
fuel flow to the burner assembly.
Fuel from the burners is ignited, resulting in an increase in jet pipe pressure (P6). This
alters the pressure ratio across the turbine (P3/P6), and the exit area of the jet pipe
nozzle is automatically increased until the correct PS/PS ratio has been restored. With
a further increase in the degree of afterburning, the nozzle area is progressively
increased to maintain a satisfactory P3/P6 ratio. Figure shown below illustrates a
typical afterburner fuel control system.
22 | Page
PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 12 - A simplified typical afterburner fuel control system.
To operate the propelling nozzle against the large 'drag' loads imposed by the gas
stream, a pump and either hydraulically or pneumatically operated rams are
incorporated in the control system. The system shown in figure below uses oil as the
hydraulic medium, but some systems use fuel.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 13 - A simplified typical afterburner nozzle control system.
Nozzle movement is achieved by the hydraulic operating rams which are pressurized
by an oil pump, pump output being controlled by a linkage from the pressure ratio
control unit. When an increase in afterburning is selected, the afterburner fuel control
unit schedules an increase in fuel pump output. The jet pipe pressure (P6) increases,
altering the pressure ratio across the turbine (P3/P6).
The pressure ratio control unit alters oil pump output, causing an out-of-balance
condition between the hydraulic ram load and the gas load on the nozzle flaps. The
gas load opens the nozzle to increase its exit area and, as the nozzle opens, the
increase in nozzle area restores the P3/P6 ratio and the pressure ratio control unit
alters oil pump output until balance is restored between the hydraulic rams and the
gas loading on the nozzle flaps.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
THRUST INCREASE – AFTERBURNING
The increase in thrust due to afterburning depends solely upon the ratio of the absolute
jet pipe temperatures before and after the extra fuel is burnt. For example, neglecting
small losses due to the afterburner equipment and gas flow momentum changes, the
thrust increase may be calculated as follows.
Assuming a gas temperature before afterburning of 640 deg. C. (913 deg. K.) and with
afterburning of 1,269 deg. C. (1,542 deg. K.). Then the temperature ratio = 1,542 =
1.69. 913.
The velocity of the jet stream increases as the square root of the temperature ratio.
Therefore, the jet velocity = ^/T.69 = 1.3. Thus, the jet stream velocity is increased by
30 per cent, and the increase in static thrust, in this instance, is also 30 per cent.
Figure 14 - Thrust increase and temperature ratio.
Static thrust increases of up to 70 per cent are obtainable from low by-pass engines
fitted with afterburning equipment and at high forward speeds several times this
amount of thrust boost can be obtained.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
High thrust boosts can be achieved on low by-pass engines because of the large
amount of oxygen in the exhaust gas stream and the low initial temperature of the
exhaust gases.
It is not possible to go on increasing the amount of fuel that is burnt in the jet pipe so
that all the available oxygen is used, because the jet pipe would not withstand the high
temperatures that would be incurred and complete combustion cannot be assured.
FUEL CONSUMPTION – AFTERBURNING
Afterburning always incurs an increase in specific fuel consumption and is, therefore,
generally limited to periods of short duration. Additional fuel must be added to the gas
stream to obtain the required temperature ratio.
Since the temperature rise does not occur at the peak of compression, the fuel is not
burnt as efficiently as in the engine combustion chamber and a higher specific fuel
consumption must result.
For example, assuming a specific fuel consumption without afterburning of 1,15
lb./hr./lb. thrust at sea level and a speed of Mach 0,9 as shown in the figure below.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 15 - Specific fuel consumption comparison.
Then with 70 percent afterburning under the same conditions of flight, the consumption
will be increased to approximately 2.53 lb./hr./lb. thrust. With an increase in height to
35,000 feet this latter figure of 2.53 lb./hr./lb. thrust will fall slightly to about 2.34
lb./hr./lb. thrust due to the reduced intake temperature.
When this additional fuel consumption is combined with the improved rate of take-off
and climb (shown in the figure below), it is found that the amount of fuel required to
reduce the time taken to reach operation height is not excessive.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
Figure 16 - Afterburning and its effect on the rate of climb.
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PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
RESEARCH PAPER:
Do a research study about the advantages and disadvantages of using performance
augmentation and thrust augmentation systems on gas turbine engines. Also specify
some safety concerns regarding the use of these augmentation components.
Use of images, figures, and tables are encouraged, as well as, including additional
topics and information.
Input your work on a A4-sized paper with your complete name, year, section, course,
and signature over printed name indicating that you are accepting the terms provided
and indicated by the honesty clause; saved as PDF file with file name, “Surname –
Module 07 Research Paper”.
ACTIVITY 01:
In regards to all the graphs indicated in this Learning Module (Figure Nos. 1, 2, 14 and
15), create a detailed explanation regarding the data specified on each graphs as
indicated. The data shown in these graphs clearly covers the entire operating concept
for both performance augmentation and thrust augmentation capabilities of gas turbine
engines.
Input your work on a A4-sized paper with your complete name, year, section, course,
and signature over printed name indicating that you are accepting the terms provided
and indicated by the honesty clause; saved as PDF file with file name, “Surname –
Module 07 Activity”.
29 | Page
PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
RUBRIC FOR RESEARCH PAPER
CRITERIA
EXCELLENT
(4 POINTS)
GOOD
(3 POINTS)
Topic focus
The topic is focused
narrowly enough for
the scope of this
assignment.
The topic is
focused but
lacks direction.
Depth of
discussion
In-depth discussion
& elaboration in all
sections of the
paper.
In-depth
discussion &
elaboration in
most sections of
the paper.
Cohesiveness
Ties together
information from all
sources. Paper
flows from one issue
to the next without
the need for
headings. Student's
writing
demonstrates an
understanding of the
relationship among
material obtained
from all sources.
For the most
part, ties
together
information from
all sources.
Paper flows with
only some
disjointedness.
Students writing
demonstrates an
understanding of
the relationship
among material
obtained from all
sources.
FAIR
(2 POINTS)
The topic is too
broad for the
scope of this
assignment.
The student has
omitted pertinent
content or
content runs-on
excessively.
Sometimes ties
together
information from
all sources.
Paper does not
flow disjointedness is
apparent.
Student's writing
does not
demonstrate an
understanding of
the relationship
among material
obtained from all
sources.
Spelling and
grammar
No spelling &/or
grammar mistakes.
Minimal spelling
&/or grammar
mistakes.
Noticeable
spelling &
grammar
mistakes.
Citations
Cites all data
obtained from other
sources. APA
citation style is used
in both text and
references.
Cites most data
obtained from
other sources.
APA citation
style is used in
both text and
refrerences.
Cites some data
obtained from
other sources.
Citation style is
either
inconsistent or
incorrect.
NEEDS
IMPORVEMENT
(1 POINT)
The topic is not
clearly defined.
Cursory discussion
in all the sections of
the paper or brief
discussion in only a
few sections.
Does not tie
together
information. Paper
does not flow and
appears to be
created from
disparate issues.
Headings are
necessary to link
concepts. Writing
does not
demonstrate
understanding any
relationships
Unacceptable
number of spelling
and/or grammar
mistakes.
Does not cite
sources.
Reference:
Research
Paper
Rubric.
(n.d.).
Retrieved
from
https://www.cornellcollege.edu/library/faculty/focusing-on-assignments/tools-forassessment/resear
30 | Page
PHILIPPINE STATE COLLEGE OF AERONAUTICS
INSTITUTE OF ENGINEERING AND TECHNOLOGY
AERONAUTICAL ENGINEERING DEPARTMENT
Learning Module 07: Performance and Thrust Augmentation
RUBRIC FOR SHORT ANSWERS
CRITERIA
Content
GOOD
(3 POINTS)
FAIR
(2 POINTS)
NEEDS
IMPORVEMENT
(1 POINT)
Answers are
accurate and
complete. Key
points are
stated and
supported.
Answers are
not
comprehensive
or completely
stated. Key
points are
addressed, but
not well
supported.
Answers are
partial or
incomplete. The
key points are not
clear. The
question is not
adequately
answered.
Well organized,
coherently
developed, and
easy to follow.
The
organization is
mostly clear
and easy to
follow.
Inadequate
organization or
development.
The structure
of the answer
is not easy to
follow.
Organization and
structure detract
from the answer.
Displays no errors
in spelling,
punctuation,
grammar, and
sentence
structure.
Displays one to
three errors in
spelling,
punctuation,
grammar, and
sentence
structure.
Displays three
to five errors in
spelling,
punctuation,
grammar, and
sentence
structure.
Displays over five
errors in spelling,
punctuation,
grammar, and
sentence
structure.
EXCELLENT
(4 POINTS)
Answers are
comprehensive,
accurate, and
complete. Key
ideas are clearly
stated, explained,
and well
supported.
Organization
(Answers
are clearly
thought out
and
articulated.)
Writing
Conventions
(Spelling,
punctuation,
grammar,
and
complete
sentences.)
Reference:
Professor,
M.
(n.d.).
Rubric
https://www.rcampus.com/rubricshowc.cfm?sp=yes
gallery.
Retrieved
from
31 | Page