This so called PPT for propulsion study for Shenyang Aerospace University. This PPT right protected by Dr. divinder K. Yadav. Its using in SAU by Lale. For all students of Aeronautical Engineering must memorize each & every words from this PPT. If you miss a single words you must fail in the Exam. Remember there is no chance to be creative or use sense you just need to use the power of memorizing.
3. Gas Turbine Fuels
Liquid hydrocarbons similar to kerosene
Some are blended with gasoline
Narrow cut/wide cut
Jet fuels are not color coded but may have
a natural pale straw colour
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4. Jet Fuel Qualities
Ease of flow
able to start readily but not be volatile
complete and rapid combustion
high calorific value
non-corrosive
lubricating
minimal fire hazard
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5. Jet Fuel Types (AVTUR)
Jet A – no gasoline blend
Jet A1 – similar to Jet A but with a lower
freezing point (also called JP-8* or F34)
Jet B – contains a gasoline blend, higher
flammability, generally for cold climates
*JP-8 has additional additives
JP-5, JP-8 - Military fuels
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6. Some Fuel Comparisons
Flash point Avtur +38oC
Avgas –400C
Volatility Avtur lower than Avgas
Avtur harbours more dissolved water
which can freeze, produce waxes and allow
microbiological growth
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8. Jet Fuel Additives
The most common fuel additives are the
anti-icing and anti-microbiocidal agents
Anti-icing additives keep entrained water
from freezing
Microbiocidal agents kill microbes fungi
and bacteria which form a slime and in
some cases a matted waste in fuel systems
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13. Fuel Heat Content
Specific gravity Avgas 0.7 approx
Avtur 0.8 approx
Avtur yields more heat than Avgas per
unit volume
Avgas yields more heat than Avtur per unit
weight 13
14. Fuel Control
The purpose of the fuel control unit is to
maintain a correct combustion zone air-to-
fuel mixture ratio of 15:1 by weight
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15. Fuel Control
To maintain the correct air-to-fuel
relationship altitude, air temperature and
aircraft speed must be considered
These variables change the density of the
air at the engine intake and consequently
the mass of air induced through the engine
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16. Fuel Control
Many signals are sent to the fuel control unit
to maintain the correct fuel-to-air ratio
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17. Fuel Control
Engine speed (N2)
Used for both steady state fuel
scheduling and acceleration/deceleration
fuel scheduling
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18. Fuel Control
Inlet Pressure (Pt2)
A total pressure signal from a probe
in the engine inlet
The pressure will be the result of
aircraft speed, altitude and ram
conditions
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20. Fuel Control
Burner Can Pressure (PS4)
A static pressure signal from within
the combustion liner
The quick response this signal gives
makes it valuable in preventing stalls,
flameouts and over-temperature
conditions
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21. Fuel Control
Inlet Temperature (Tt2)
A total temperature (actual plus
ram) signal from the inlet
This signal provides the control with
an airflow density value against which
a fuel schedule can be established
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45. Bleed Air Systems
Bleed air is tapped from various
compressor stages for use in the engine and
aircraft
Bleed air is typically 4 – 5% of total engine
airflow
A reduction in engine airflow results in a
reduction in engine performance
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54. Engine Anti-ice System
• The engine anti-ice system uses engine bleed air
to provide engine cowl inlet ice protection.
•The system can be operated in-flight or on
ground.
•The left and right engines have identical,
independent anti-ice systems. This allows the
remaining system to operate, if one engine fails.
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