Jet engine parts and their functions
A simplified two-spool, high-bypass turbofan. This educational model shows the main assemblies; it is not a manufacturing drawing or a specific production engine.
Inlet lip
Smoothly guides incoming air toward the fan and limits flow separation.
Front of nacelle · Stationary
Representative material: Aluminum alloy
Fan
Accelerates a large mass of air. Most passes around the core through the bypass duct, producing much of the thrust in a high-bypass turbofan.
Engine front · Low-pressure spool rotation
Representative material: Titanium alloy or composite
Spinner
A streamlined nose cone guides incoming air outward toward the fan blades.
Fan center · Rotates with fan
Representative material: Aluminum or composite
Nacelle
Encloses the engine and forms the outer wall of the bypass flow path.
Outer engine enclosure · Stationary
Representative material: Composite sandwich structure
Bypass outlet guide vanes
Straighten fan discharge in the bypass duct and support the core within the nacelle.
Behind fan, outside core · Stationary
Representative material: Titanium or composite
Low-pressure compressor
Raises core-air pressure before it enters the high-pressure compressor.
Forward core · Low-pressure spool rotation
Representative material: Titanium alloy
High-pressure compressor
Successive rotor and stator rows raise air pressure. Stators slow and redirect flow between rotor rows.
Core ahead of combustor · Rotors turn on high-pressure spool
Representative material: Titanium and nickel alloys
Core casing
Supports stationary compressor and turbine structures and contains the core gas path.
Around core · Stationary
Representative material: Titanium and nickel alloys
Fuel injectors
Atomize fuel into compressed air around the annular combustor. Igniters establish the flame during starting or relight.
Combustor entrance · Stationary
Representative material: Heat-resistant nickel alloy
Annular combustor
Burns fuel continuously in compressed air. Cooling air protects the liner; hot gas then flows to the turbines.
Between compressor and turbine · Continuous combustion
Representative material: Nickel superalloy with thermal coating
High-pressure turbine
Extracts energy from hot gas to drive the high-pressure compressor through its shaft.
Immediately after combustor · High-pressure spool rotation
Representative material: Cooled nickel superalloy
Low-pressure turbine
Extracts further energy to drive the fan and booster through the inner shaft.
Behind high-pressure turbine · Low-pressure spool rotation
Representative material: Nickel superalloy
Concentric spool shafts
Two concentric shafts connect each turbine to its compressor system. The inner low-pressure shaft drives the fan and booster.
Engine centerline · Two independent rotational speeds
Representative material: High-strength steel
Core exhaust nozzle
Accelerates the remaining core gas rearward. Core exhaust and bypass flow together produce thrust.
Engine rear · Stationary
Representative material: Heat-resistant nickel alloy
Reference: NASA Glenn — Turbofan engine
Connect the steps
- Fan
- Booster and compressor
- Combustor
- Turbines
- Nozzles
Similar-looking blades do different work
Compressor blades transfer shaft work into the airflow. Turbine blades extract work from hot gas and deliver it through a shaft. Seeing blades in both locations does not mean their purpose is the same. Their surroundings and position in the flow path reveal which energy transfer is taking place.
Try it in 3D
Select a compressor and a turbine. Compare their positions and identify the assemblies connected by their shaft.
Open the related explorer →Does a turbine create energy?
No. It converts some of the gas energy into mechanical work. Combustion supplies heat, and useful exhaust energy must remain to support thrust.