M15.1 Fundamentals Flashcards
What is energy typically defined as?
Something that gives us the capacity to perform work.
How are work and energy measured?
In joules.
What are the two types of energy?
- Potential
- Kinetic
Define potential energy.
Energy at rest or energy that is stored.
Define kinetic energy.
Energy in motion.
What is Newton’s First Law of Motion also known as?
The law of inertia.
What does Newton’s Second Law of Motion express?
The interplay between force and motion.
What is the formula for Newton’s Second Law?
Force = Mass x Acceleration.
What is Newton’s Third Law of Motion also referred to as?
The law of action and reaction.
What does the Brayton cycle describe?
The thermodynamic cycle of a gas turbine engine that produces thrust.
What are the four stages of the Brayton cycle?
- Intake (suck)
- Compression (squeeze)
- Expansion (bang)
- Exhaust (blow)
What happens during the intake stage of the Brayton cycle?
Air enters at ambient pressure and at a constant volume.
What is isobaric heating in the Brayton cycle?
Heat is added to the air in the combustion chamber at constant pressure.
What are the four ideal changes of state?
- Isobaric
- Isochoric
- Isothermal
- Isentropic
Which changes of state are important for aircraft gas turbine engines?
- Isobaric
- Isentropic
What does force represent?
The intensity of a thrust or input.
What is the unit for force in the metric system?
Newtons (N).
What is work defined as?
When a force is moved through a distance, in the direction of the force.
What are the two factors involved in calculating work?
- Force
- Movement through a distance
What is the SI unit of work?
Joule (J).
What does power involve in relation to work?
The rate of doing work over time.
What is the SI unit of power?
Watt (W).
Define motion.
A continuing change of position or place.
What is the difference between speed and velocity?
Speed does not include direction; velocity includes both speed and direction.
What is acceleration defined as?
The rate of change of velocity.
What are the two main types of aircraft engines?
- Piston type engines
- Gas turbine engines
What is a key advantage of gas turbine engines over piston engines?
Can operate at very high altitudes.
What type of engine produces thrust in aircraft?
Gas turbine engines.
What are the types of gas turbine engines used on aircraft?
- Turbojet engines
- Turbofan engines
- Turboprop engines
- Turboshaft engines
What is a significant disadvantage of turbojet engines?
High fuel consumption.
What is the primary function of turbofan engines?
Produce thrust with better efficiency than turbojets.
What is the advantage of turboprop engines?
Very fuel efficient at mid-range speeds.
What is a turboshaft engine primarily used for?
To drive machinery instead of producing thrust.
What are the main sections of a gas turbine engine?
- Air inlet
- Compressor section
- Combustion section
- Turbine section
- Exhaust section
- Accessory section
What does the ‘cold section’ of a gas turbine engine refer to?
Parts from the inlets up through the compressors.
What does the ‘hot section’ of a gas turbine engine refer to?
Areas past the compressors from the combustion chambers through the exhaust.
What are the main sections of a turbine engine?
Combustion section, Turbine section, Exhaust section, Accessory section
The sections include the diffuser, combustor, Low-pressure Turbine (LPT), High-pressure Turbine (HPT), Turbine Exhaust Case (TEC), and main gearbox.
What does the ‘cold section’ of a turbine engine refer to?
Parts of the engine from the inlets up through the compressors and/or diffusers
This section includes components that operate at lower temperatures compared to the hot section.
What does the ‘hot section’ of a turbine engine refer to?
Areas past the compressors from the combustion chambers through the exhaust
This section involves components that operate at high temperatures.
List the advantages of modular engine construction for the engine manufacturer.
- The rotating module parts can be pre-balanced
- Fewer spare engines are needed in stock
- More flexibility when changes are made to individual engine parts
- Main engine modules can be easily stored and transported
These advantages contribute to efficiency in manufacturing and inventory management.
List the advantages of modular engine construction for the engine operator.
- Modules can be removed and replaced with minimum disturbance to other nearby engine parts
- No re-balancing is required after a module change
- Most modules can be replaced while the engine remains on the aircraft
- Less need for spare parts and modules can be easily transported
These benefits enhance maintenance efficiency and reduce downtime.
What is a further advantage of the modular design in terms of repairs?
Replacement of a module is often considered a minor repair and not a shop repair
This allows maintenance to be performed by a maintenance organization rather than requiring an engine overhaul organization.
What is the main design aim for engine materials?
Materials must be strong enough for their tasks, as light and cheap as possible
This balance is crucial for performance and cost-effectiveness in engine design.
What are typical materials used in modern jet engines?
- Aluminium alloy
- Ceramic material
- Composite material
- Cobalt base alloy
- Nickel base alloy
- Corrosion resistant steel alloy
- Titanium base alloy
These materials are selected for their specific properties suitable for high-performance engine components.
