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Sungjae:
From the project, I could understand concepts and principles of Jet Engine. To summarize, a Jet Engine is a type of reaction engine discharging a fast-moving jet that generates thrust by jet propulsion. This Jet engine is broadly being utilized in various parts as a key technology of Aerospace Engineering.

By searching for data about Jet Engines, I could learn components of jet engines, operation, and differences between Turbojet Engine and Turbofan Engine. According to NASA, developments of Jet Engine was so revolutionary that it had a great influence on aerospace engineering. As Jet engine made improvements on the world, I hope to contribute to the development of Aerospace Engineering.

Cheonha:
Before I do this project, I just thought the jet engine as 'fast, strong, and ,first of all cool thing'. I could realize thay the jet engine is more complex and segmentalized engine, which is very different from my thought. Thanks to this project, I could learn about the kinds of jet engine(Turbojet engine, and turbofan engine) and that these two kinds are quite different in the way they produce own propulsion. In addition, I specially focused on the 'nozzle' , which was unfamilliar part of engine to me. Searching many data, I could learn nozzle is designed to control the flow of fliud and also used in rocket, while the fan is not. Like the past when Jet engine was a revolution, and future, I think revolutionary time will be coming soon. And I wish I am in the center of that future by designing new kinds of engine.

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From this video, I could find informations about the history of invention and developments of the Jet engines.

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Although the invention of the jet engine can be traced back to the aeolipile made around 150 B.C., Dr. Hans von Ohain and Sir Frank Whittle are both recognized as being the co-inventors of the jet engine as we know it today, even though each worked separately and knew nothing of the other's work.

Jet propulsion is defined simply as any forward movement caused by the backward ejection of a high-speed jet of gas or liquid. In the case of air travel and engines, jet propulsion means that the machine itself is powered by jet fuel.

While Von Ohain is considered the designer of the first operational turbojet engine, Whittle was first to register a patent for his schematics of a prototype, in 1930. Von Ohain obtained a patent for his prototype in 1936, and his jet was the first to fly in 1939. Whittle's took off for the first time in 1941.

While von Ohain and Whittle may be the acknowledged fathers of modern jet engines, many grandfathers came before them, guiding them as they paved the way for the jet engines of today.

The aeolipile of 150 B.C. was created as a curiosity and never used for any practical mechanical purpose. In fact, it wouldn't be until the invention of the fireworks rocket in the 13th century by Chinese artists that a practical use for jet propulsion was first implemented.

In 1633, Ottoman Lagari Hasan Çelebi used a cone-shaped rocket powered by jet propulsion to fly up into the air and a set of wings to glide it back to a successful landing. However, because rockets are inefficient at low speeds for general aviation, this use of jet propulsion was essentially a one-time stunt. In any event, his effort was rewarded with a position in the Ottoman Army.

Between the 1600s and World War II, many scientists experimented with hybrid engines to propel aircraft. Many used one of the piston engine's forms-including air-cooled and liquid-cooled inline and rotary and static radial engines-as the power source for aircraft.

Sir Frank Whittle was an English aviation engineer and pilot who joined the Royal Air Force as an apprentice, later becoming a test pilot in 1931.

Whittle was only 22 when he first thought to use a gas turbine engine to power an airplane. The young officer tried unsuccessfully to obtain official support for study and development of his ideas but was ultimately forced to pursue his research on his own initiative.

He received his first patent on turbojet propulsion in January 1930.

Armed with this patent, Whittle again sought funding to develop a prototype; this time successfully. He began construction of his first engine in 1935 -- a single-stage centrifugal compressor coupled to a single-stage turbine. What was meant to be only a laboratory test rig was successfully bench-tested in April 1937, effectively demonstrating the feasibility of the turbojet concept.

Power Jets Ltd. -- the firm with which Whittle was associated -- received a contract for a Whittle engine known as the W1 on July 7, 1939. In February 1940, the Gloster Aircraft Company was chosen to develop the Pioneer, the small engine aircraft the W1 engine was earmarked to power; the historic first flight of the Pioneer took place on May 15, 1941.

The modern turbojet engine used today in many British and American aircraft is based on the prototype invented by Whittle.

Hans von Ohain was a German airplane designer who obtained his doctorate in physics at the University of Göttingen in Germany, later becoming the junior assistant to Hugo Von Pohl, director of the Physical Institute at the university.

At the time, von Ohain was investigating a new type of aircraft engine that did not require a propeller. Only 22 years old when he first conceived the idea of a continuous cycle combustion engine in 1933, von Ohain patented a jet propulsion engine design in 1934 very similar in concept to that of Sir Whittle, but different in internal arrangement.

Upon the mutual recommendation of Hugo von Pohl, Von Ohain joined German aircraft builder Ernst Heinkel, at the time seeking assistance in new airplane propulsion designs, in 1936. He continued development of his jet propulsion concepts, successfully bench-testing one of his engines in September 1937.

Heinkel designed and constructed a small aircraft known as the Heinkel He178, to serve as a testbed for this new propulsion system, which flew for the first time on August 27, 1939.

Von Ohain went on to develop a second, improved jet engine known as the He S.8A, which was first flown on April 2, 1941.

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Although the invention of the jet engine can be traced back to the aeolipile made around 150 B.C., Dr. Hans von Ohain and Sir Frank Whittle are both recognized as being the co-inventors of the jet engine as we know it today, even though each worked separately and knew nothing of the other's work.

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This course will deal with the general concepts and characteristics of various kinds of airbreathing engines such as turbo prop, turbo shaft, turbo fan, turbo jet, ram jet and scram jet. It will also examine the micro-engines used in MAV(Micro Aerial Vehicle) and discuss the exhaust gas and noise reduction methods.

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This course will deal with the general concepts and characteristics of various kinds of airbreathing engines such as turbo prop, turbo shaft, turbo fan, turbo jet, ram jet and scram jet. It will also examine the micro-engines used in MAV(Micro Aerial Vehicle) and discuss the exhaust gas and noise reduction methods.

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Course List - Undergraduate - AEROSPACE ENGINEERING, SNU

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Courses offered SNU Course Registration System

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Cold section:

Air intake (inlet) — For subsonic aircraft, the inlet is a duct which is required to ensure smooth airflow into the engine despite air approaching the inlet from directions other than straight ahead. This occurs on the ground from cross winds and in flight with aircraft pitch and yaw motions. The duct length is minimised to reduce drag and weight] Air enters the compressor at about half the speed of sound so at flight speeds lower than this the flow will accelerate along the inlet and at higher flight speeds it will slow down. Thus the internal profile of the inlet has to accommodate both accelerating and diffusing flow without undue losses. For supersonic aircraft, the inlet has features such as cones and ramps to produce the most efficient series of shockwaves which form when supersonic flow slows down. The air slows down from the flight speed to subsonic velocity through the shockwaves, then to about half the speed of sound at the compressor through the subsonic part of the inlet. The particular system of shockwaves is chosen, with regard to many constraints such as cost and operational needs, to minimize losses which in turn maximizes the pressure recovery at the compressor.

Compressor or fan — The compressor is made up of stages. Each stage consists of rotating blades and stationary stators or vanes. As the air moves through the compressor, its pressure and temperature increase. The power to drive the compressor comes from the turbine (see below), as shaft torque and speed.

Bypass ducts deliver the flow from the fan with minimum losses to the bypass propelling nozzle. Alternatively the fan flow may be mixed with the turbine exhaust before entering a single propelling nozzle. In another arrangement an afterburner may be installed between the mixer and nozzle.

Shaft — The shaft connects the turbine to the compressor, and runs most of the length of the engine. There may be as many as three concentric shafts, rotating at independent speeds, with as many sets of turbines and compressors. Cooling air for the turbines may flow through the shaft from the compressor.

Diffuser section: - The diffuser slows down the compressor delivery air to reduce flow losses in the combustor. Slower air is also required to help stabilize the combustion flame and the higher static pressure improves the combustion efficiency.

Hot section:

Combustor or combustion chamber — Fuel is burned continuously after initially being ignited during the engine start.

Turbine — The turbine is a series of bladed discs that act like a windmill, extracting energy from the hot gases leaving the combustor. Some of this energy is used to drive the compressor. Turboprop, turboshaft and turbofan engines have additional turbine stages to drive a propeller, bypass fan or helicopter rotor. In a free turbine the turbine driving the compressor rotates independently of that which powers the propellor or helicopter rotor. Cooling air, bled from the compressor, may be used to cool the turbine blades, vanes and discs to allow higher turbine entry gas temperatures for the same turbine material temperatures.**A blade with internal cooling as applied in the high-pressure turbine

Afterburner or reheat (British) — (mainly military) Produces extra thrust by burning fuel in the jetpipe. This reheating of the turbine exhaust gas raises the propelling nozzle entry temperature and exhaust velocity. The nozzle area is increased to accommodate the higher specific volume of the exhaust gas. This maintains the same airflow through the engine to ensure no change in its operating characteristics.

Exhaust or nozzle — Turbine exhaust gases pass through the propelling nozzle to produce a high velocity jet. The nozzle is usually convergent with a fixed flow area.

Supersonic nozzle — For high nozzle pressure ratios (Nozzle Entry Pressure/Ambient Pressure) a convergent-divergent (de Laval) nozzle is used. The expansion to atmospheric pressure and supersonic gas velocity continues downstream of the throat and produces more thrust.

Source: https://en.wikipedia.org/wiki/Jet_engine

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A jet engine is a type of reacton gengine discharging a fast-moving jet that generates thrust by jet proplusion. Jet engines move the airplane forward with a great force that is produced by a tremendous thrust and causes the plane to fly in high velocity. There is a principle that all jet engines share to work.

1. The engine sucks air in at the front with a fan.
2. A compressors raises the pressure of the air. The compressor is made with may blades attatched to a shaft.
3. The blades spin at hihg and compress or squeeze the air.
4. The compressed air is then sprayed with fuel and an electric spark lights the mixture.
5. The burning gases expand and blast out through the nozzle, it passes through another group of blades called the turbine.
6. The turbine is attated to teh smae shaft as the comprasser. Spinning the turbine causes th e compressor to spin.
7. This proccess is repeated to operate.

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How does a jet engine work? What are the parts of the engine? Are there many types of engines?

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Propulsive efficiency comparison for various gas turbine engine configurations

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Propulsive efficiency comparison for various gas turbine engine configurations

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Source: https://en.wikipedia.org/wiki/Jet_engine

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Turbojet Engine is a simple turbine engine that produces all of its thrust from the exhaust from turbine section. However, since all of it must burn tuel, which means it is inefficent.

The Turbofan Engine, which is more efficient, primarily drives a fan at the front of the engine. Most engines drive the fan directly from the turbine. There are generally at least two sparate shfts to allow the fan to spin slopwer than the inner core of the engine.

The fans surrounded by a cowl which guides the air to and from the fan. Part of the air enters the turbine section of the engine, and the rest is bypassed around the engine.

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Both engines use a turbine for power. This is where the "turbo" part of the name comes from. In a turbine engine, air is compressed and then fuel is ignited in this compressed air. The energy produced by the ignition turns the turbine. The turbine is then able to drive both the compressor at the front of the engine and also some useful load. In airplanes, it produces thrust.

The first jet engine was a turbojet. This is a simple turbine engine that produces all of its thrust from the exhaust from the turbine section. However, because all of the air is passing through the whole turbine, all of it must burn fuel. This means it is inefficient, and the solution is the turbofan.

In a turbofan, the turbine primarily drives a fan at the front of the engine. Most engines drive the fan directly from the turbine. There are usually at least two separate shafts to allow the fan to spin slower than the inner core of the engine. The fan is surrounded by a cowl which guides the air to and from the fan. Part of the air enters the turbine section of the engine, and the rest is bypassed around the engine. In high-bypass engines, most of the air only goes through the fan and bypasses the rest of the engine and providing most of the thrust.

In a turboprop, the turbine primarily drives a propeller at the front of the engine. There is no cowl around the prop. Some air enters the turbine, the rest does not. The propeller is geared to allow it to spin slower than the turbine. Although this diagram shows only a single shaft, many turboprops have two, with a high pressure shaft driving the compressor and a low pressure shaft driving the propeller. Some engines such as the popular PT6 also reverse the flow direction multiple times.

Turboprops are more efficient at lower speeds since the prop can move much more air with a smaller turbine than the fan on a turbofan engine. The cowl around the turbofan's large fan allows it to perform better than an open propeller at high speeds, but limits the practical size of the fan.

At supersonic speeds, turbojets have more of a performance benefit. They develop all of their thrust from the high velocity turbine exhaust, while turbofans supplement that with the lower velocity air from the fan. Since the air from the fan is also not compressed nearly as much as the core turbine flow, it is also harder to prevent the flow from going supersonic and causing losses.

The Concorde used turbojets because it was designed to cruise for long periods at supersonic speeds. Modern fighter jet engines are turbofans, which provide a compromise between efficiency and speed.

There are other benefits and drawbacks between turbojets, turbofans, and turboprops, but I think they are beyond the scope of this question.

Work has been done on creating a "propfan" engine, in an attempt to get the efficiency of a turboprop and the speed of a turbofan. They have yet to come up with a viable design.

Elsewhere in aviation, turbine engines are used in

helicopters, as a turboshaft engine driving the rotors instead of a propeller, and with a freewheeling clutch to enable autorotations

APU s in jet aircraft and large turboprop aircraft

Turbines also find use outside of aviation in power plants (to generate electricity), and even vehicles (like the Abrams tank).

Turbocharged piston engines use a turbine much differently from the examples above. Instead of being the primary power source, the turbine only assists the piston engine. A turbocharger uses a turbine to compress air sent to the engine intake. The increased compression helps the engine generate more power. The turbine of a turbocharger is driven by engine exhaust gasses, and a supercharger is similar but is directly powered by the engine. See the Wikipedia page for more detail.

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What is the difference between a turbofan and a turboprop engine?

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I'm not an aircraft expert and I just realized that there are two different terms - turbofan and turboprop. I always had them combined in my head as a term for a large jet engine (like you would se...

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Representative moments for Jet Engine Tests

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Representative moments for Jet Engine Tests

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The video is for visual sources for testing Jet Turbines. This marterial is especiallly focused on Turbines, so you can visuallly learn how jet engine extracts energy from the hot gases leaving the combustor.

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TOP 5 MOST HARD TEST TURBINES (ENGINES) AIRCRAFT | CRASH  | -=1 PART=- -=HD=-

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Dependence of propulsion efficiency upon the vehicle speed/exhaust velocity ratio for air-breathing jet and rocket engines.

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Dependence of propulsion efficiency upon the vehicle speed/exhaust velocity ratio for air-breathing jet and rocket engines.

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Source: https://en.wikipedia.org/wiki/Jet_engine

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1. Specific impulse as a function of speed for different jet types with kerosene fuel.

2. Theoretical maximum H2 fuel in air is much higher than Theoretical maximum HC fuel in air.

3. Efficiency per unit distance (per km or mile) is roughly independent of speed for jet engines.

Soruce:  https://en.wikipedia.org/wiki/Jet_engine

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Source: https://en.wikipedia.org/wiki/Jet_engine

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Source: https://en.wikipedia.org/wiki/Jet_engine

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Learning materials for understanding Jet Engine principles. 

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Learning materials for understanding Jet Engine principles. 