How Jet Engines Work
Applying Sir Isaac Newton’s 3rd Law of Motion, along with four basic functions, the Turbofan Jet Engine has changed the world as we knew it, a mere 82 years ago. The jet engine has become the Gold Standard of airplane power – called “forward thrust”. This aircraft engine makes possible both rapid acceleration and cost-effective travel city-to-city and around the globe. As a pilot, the necessity to know the basic fundamentals of the turbofan engine is essential.
The Five Basics of a Jet Engine
Intake / Inlet:
The air intake is effectively a conduit at the head of the engine. The air inlet may appear straightforward, but it’s extremely crucial! The intake’s role is to efficiently turn the air into the compressor blades. At lesser velocities, the intake is required to aid in the loss of flow of air to the engine. Then, with military jets at ultrasonic rates of speed, the intake is necessitated to reduce the air flow below 767 miles per hour.
Compression:
The compressor is propelled by the turbine in the hindmost section of the Turbofan Jet Engine. Its duty is to condense the inbound air, drastically enhancing the atmospheric pressure. The compressor is a sequence of fans, each one with reduced and miniature fins in place. As air goes through and through every compressor phase, it gets more dense.
Power at Shaft Burner:
After compression comes combustion. The elevated, pressurized air is blended with aviation fuel, then the mix explodes in a contained manner. As the air & fuel concoction burns up, it continues out of the engine, headed for the turbine.
Turbine:
Turbofan Jet engines operate incredibly lean, with 50 parts air to every one part of fuel.
The turbine is a further progression of fans, which perform like a aerogenerator, attracting momentum from the great velocity of air going out of it. The turbine fins are attached to, and drive a rod, which is also linked to the compressor propellers at the head of the engine.
Exhaust Nozzle:
The elevated pace of the ignited air & fuel blend departs the engine via a discharge outlet. As the extreme velocity of air escapes the back of the engine, it generates thrust which drives the airplane faster, forward, and higher!
Now more detail…
Physics:
As many in the aviation business would deem the above as “Suck, Squeeze, Bang, Blow” the physics behind this monumental task is quite extraordinary. The Venturi Effect and the Ideal Gas Law need to occur, or lift will not be generated. The Venturi Effect is when something like a long tube has a big opening, yet a small end. When forcing something like water or air through the larger hole, the water or air has to travel faster exiting the smaller hole. The Ideal Gas Law pertains to temperature to pressure, volume, and the amount of air. The hotter the gas or air, the larger or bigger the volume. Add in the Conservation of Momentum, then we are really taking off!
Turbofan Design:
The word Turbofan was generated by blending turbine and fan into one word. When deconstructing the Turbofan, imagining the nine components of this ducted fan being driven by a turbojet, all contributing to the thrust, will make more of an impression.
1). Nacelle:
This is the outside of the engine we all see in huge airliners, and smaller aircraft alike. The Nacelle needs to be streamlined to fit what it contains for aviation needs.
2). Fan:
This is what brings breathe to an aircraft. The ducted portion of the fan forces air rearwards. While the turbo section from the shaft of the fan propels power-driven momentum from combustion via the turbine. The fan can be thought of as a high-tech propeller inside a duct.
3). Low-Pressure Compressor:
The head portion of a dual-spool compressor, also known as an N1 compressor or a low-speed compressor. It is powered by the final phase of a turbine. There are four low-pressure stages in a Turbofan engine.
4). High-Pressure Compressor:
The subsequent phased compressor in a double reel gas turbine motor. It is dubbed an N2 compressor. A high-pressure compressor is the only one spun by the initial system of an airplane. Ten high-pressures stages allow for essential combustion throughout flight.
5). Combustion Chamber:
The uninterrupted process for turbojet engines to combust fuel at high pressure in a defined space.
6). High-Pressure Turbine:
Many common turbofans utilize a high-proficiency, 2-phase HP turbine to drive the HP compressor. Contemporary Air Force Turbofans have a tendency to employ a specific High-Pressure turbine phase and a modest High-Pressure compressor.
7). Low-Pressure Turbine:
Current domestic-styled turbofans need multi-stage LP turbines (anywhere from 3 to 7). The amount of phases necessary varies on the motor’s cyclical circumvention ratio and the lift required. A pitched, ducted, or geared fan may decrease the number of necessary LPT phases in some applications for thrust and lift.
8). Core Nozzle:
The core nozzle allows movement, or flow of air/fuel mix, to exit the center nozzle as the fan flow exits the annular outlet. Blending of the two flows offers a little thrust enrichment. and these nozzles also tend to be quieter than convergent nozzles.
9). Fan Nozzle:
The fan nozzle is the section of a jet engine that squeezes the air/fuel mixture going through to improve thrust. The fan nozzle generates pressure, which is used in the driving force of thrust.
What Are Stator Vanes?
Stator vanes are essential components inside the annular compressors that play a key role for the production capability of power generation of thrust for air travel. While the compressor is in use, fins turn around at extreme rates of speed to generate rotating kinetic energy all through the passage of gas and air. These stationary vanes, or fins, force either air, fuel, or both throughout the entire engine, from narrow passageways to large. Stator vanes are fixed parts that provide conversion of this revolving energy into constant pressure due to the transformation in movement, performing a crucial role in the process and effectiveness of the entire thrust of the aircraft.
In Conclusion
Whether you seek to master a Cessna 172S Skyhawk, a Piper PA-44 Seminole, or move into commercial aviation like an Airbus A220, starting on the ground first at Leopard Aviation will get you soaring in the deep blue skies within days! Our highly trained staff will have you feeling exhilarated, as though you have joined an elite group that has risen to the challenges of triumphs of piloting your own Turbofan aircraft! Allow Leopard Aviation to instruct you further about the fascinating Turbofan Jet Engine and piloting these gorgeous aircrafts. Imagine where this new skill can take you, your family, business partners and clients, to the endless bounds of air travel, and the excitement it embraces!