POWERPLANT - GAS TURBINE ENGINE Flashcards
What is the primary difference between the Brayton cycle and the Otto cycle in terms of process?
Brayton cycle is a constant pressure process
Which component is essential for the Brayton cycle in jet engines but not present in reciprocating engines?
Compressor
In the Brayton cycle, what happens during the compression phase?
Air is compressed, raising its pressure and temperature
During which part of the Brayton cycle is energy extracted to perform work?
Expansion
In a typical jet engine operating on the Brayton cycle, where does the combustion process occur?
In the combustion chamber
How does the Brayton cycle improve the efficiency of jet engines compared to piston engines using the Otto cycle?
By continuously compressing and expanding air
Whch of the following best describes the sequence of processes in a Brayton cycle?
Intake, Compression, Combustion, Expansion, Exhaust
Which component in a turbojet engine compresses the air?
Compressor
What is the purpose of an air intake in a jet engine?
Supply air to the compressor
What is the function of the compressor in a jet engine?
Increase the pressure of the incoming air
How is fuel typically ignited in a jet engine?
Combustion chamber igniters
What is the purpose of the combustor in a jet engine?
To burn the fuel-air mixture
What is the purpose of the turbine in a jet engine?
. Increase air pressure
What is the primary function of the turbine in a jet engine?
To extract energy from the combustion gases
In a turbine engine, what is the function of the compressor section?
To increase the pressure of the air before combustion
Which component in a jet engine extracts energy from the high-speed exhaust gases?
Turbine
What is the primary purpose of the afterburner in some jet engines?
To increase thrust by burning additional fuel in the exhaust stream
How is the speed of a turbojet engine primarily controlled?
Adjusting the fuel flow
Which type of ignition system is commonly used in jet engines?
Electric spark ignition
What is the primary purpose of the reduction gear in a turboprop engine?
Decrease propeller RPM
How is the thrust generated in a turbofan engine?
By the bypassed air and exhaust gases
What is the function of the accessory gearbox in a jet engine?
Power auxiliary components
Which type of lubrication system is commonly used in jet engines?
Pressure lubrication
What is the purpose of the diffuser in a jet engine?
Decrease air velocity and increase pressure
What is the main function of the turbine blades in a jet engine?
Extract energy from the exhaust gases
Which type of cooling system is typically used in jet engines?
Air cooling
How is the speed of a turboprop engine controlled?
Changing the propeller pitch
Which type of turbine is used to drive the fan in a high-bypass turbofan engine?
Low-pressure turbine
Which type of turbine blade is used in the high-temperature section of a jet engine?
Ceramic-coated blades
What does the term ‘compressor pressure ratio’ refer to in a jet engine?
c. Ratio of compressor outlet pressure to inlet pressure
What is the purpose of a bypass duct in a turbofan engine?
Allow air to bypass the engine core
What is ‘hot section’ maintenance in a jet engine?
Maintenance of the combustor, turbine, and exhaust sections
What is the purpose of a turbine blade shroud in a jet engine?
To reduce vibration and blade tip leakage
What is the primary function of a fuel control unit in a jet engine?
To manage the fuel flow to maintain the desired engine speed and power output
What is a ‘choked’ nozzle in a jet engine?
A nozzle that limits the maximum airflow
What is the purpose of an igniter in a jet engine?
To ignite the fuel-air mixture during start-up
What is the primary advantage of using a turbofan engine over a turbojet engine?
Higher fuel efficiency
What is the function of an aftercooler in a reciprocating engine?
To cool the compressed air before it enters the combustion chamber
What is the purpose of a ‘variable stator vane’ in a jet engine compressor?
To adjust the airflow through the compressor for optimal performance
What type of bearing is commonly used in the turbine section of a jet engine?
Ball bearing
What is the purpose of a ‘bleed valve’ in a jet engine?
To control airflow through the compressor
What is the function of a ‘surge tank’ in an aircraft fuel system?
To collect overflow fuel
What is the purpose of a ‘turbine nozzle’ in a jet engine?
To direct the flow of hot gases onto the turbine blades
What is the purpose of a ‘thrust reverser’ in a jet engine?
To reverse the direction of thrust to help slow the aircraft during landing
What is a ‘hot start’ in a jet engine?
A start in which the engine’s EGT exceeds safe limits
The main purpose of engine oil in a turbine engine is to:
Lubricate and cool bearings
What is the function of a fuel flow transmitter in a turbine engine?
To measure the rate of fuel consumption
The term “hot section inspection” in turbine engine maintenance refers to inspecting:
The combustion chamber and turbine section
What is the purpose of a fire detection system in a turbine engine?
To detect and alert of any fire in the engine compartment
Which type of fuel filter are used in turbine engines?
Metal mesh filter
What does ‘N2’ indicate in a dual-spool jet engine?
The speed of the high-pressure compressor
