30 years of development and future prospects of a new tidal stream of a jet engine for aircraft "Geared Turbo fan"

ByPW 1000 G

Just a few months left until the end of 2015, but in the world of passenger aircraft a jet engine with a new mechanism that was not traditional in the past few months "Geared turbofan engine(GTF engine) "scheduled for the first flight of the aircraft. A GTF engine with high fuel efficiency and environmental friendliness is an engine that incorporates a new mechanism based on a conventional jet engine, but its development has spent 30 years and its future jet engine It is thought that it also possesses the possibility to change the way of it.

Pratt's PurePower GTF: Jet Engine Innovation Took Almost 30 Years - Bloomberg Business
http://www.bloomberg.com/news/articles/2015-10-15/pratt-s-purepower-gtf-jet-engine-innovation-took-almost-30-years

◆ What is Geared Turbo Fan Engine (GTF Engine)?
Manufacture jet engines for aircraftPratt & WhitneyGeared Turbo fan engine developed by P & amp; W company "PW 1000 G"Is an engine that realizes high efficiency in a dimension that was not traditional by eliminating the compromise point where conventional jet engines could not be avoided. According to the figures published by P & amp; W, the fuel consumption is reduced by 16% compared with jet engines with the best performance at the moment, and the engine noise on the ground is actually as low as 75% It has been with.


The PW 1000 G engine has performance matching the single pass aircraft and narrow body machine of 100 to 200 passengers, and it is equipped with Airbus · A 320 machineBombardier · C Series,Embraer · E-Jet,Irukut MS-21, And gather attention as a domestic product for the first time in 40 yearsMitsubishi · MRJIt is decided to be adopted for the aircraft such as. In 2014, Airbus · A320neo equipped with this engine is doing the first flight, and we have been walking the way to the first flight after following procedure such as type certification.

A320neo Completes First Flight | Commercial Aviation content from Aviation Week
http://aviationweek.com/commercial-aviation/a320neo-completes-first-flight

A movie showing the low noise of the GTF engine is here. Although the noise of the conventional jet engine and the GTF engine generated when taking off the airport are alternately reproduced, as you hear this movie clearly the noise is seen being reduced. Especially after the "Overhead" where the aircraft passes over the head, low frequency sound like a roar is cut greatly, and you can catch a glimpse of the state of engine sound which is very different from the conventional one.

PurePower® Engine: You Have to Hear It to Believe It - YouTube


The "compromise" that the GTF engine overcame was due to the mechanism that the jet engine had. Especially, among jet engines, it is currently the main streamTurbo fan engineIn its mechanism, it had the property that it can not escape from compromise.

◆ "Compromise" that could not escape
Unlike the original "jet engine" which burns fuel and obtains thrust by injecting high-speed combustion gas, the turbofan engine pushes out the air by rotating a large fan in front of the body, We are making it a driving force to advance. In the latest type turbofan engine, the air flow rate by this fan is increased,Boeing 787"Trent 1000" engine realizes "high bypass ratio" that discharges 11 times the air of the combustion gas backward, achieving high efficiency and low noise.

Trent series Turbo fan engine | Turbo fan engine for passenger aircraft | Kawasaki Heavy Industries Gas Turbine Business Center


Although it was a turbofan engine that realizes high efficiency, there is actually a weak point that it can not escape from a certain compromise because of its mechanism. In the turbofan engine, high temperature and high pressure gas generated by the combustion of jet fuelTurbineThe axis of the engine was rotated by spraying it on the same shaftfanAlthough it is producing thrust by rotating it, the rotation speed at which "turbine" and "fan" operate most efficiently is completely different between them. Therefore, pursuing the efficiency of the turbine makes the rotation of the fan too fast, conversely there is a dilemma that the efficiency of the turbine decreases if the efficiency of the fan is obtained.

ByDuesentrieb

Developed to eliminate this dilemma, the turbine and fan are equipped with the mechanism that can operate most efficientlyGTF engineThat's why. The GTF engine looks like the picture belowPlanetary GearOn the axis and has a mechanism to resolve the conventional compromise by reducing the rotation speed of the shaft and telling it to the fans.

ByPW 1000 G

Although the idea of ​​the GTF engine itself existed since the 1980's, its realization has been a long month of 30 years, a lot of people and budget was brought in. By introducing hundreds of human resources and over $ 10 billion (about 1 trillion yen) of funds across P & W companies, we realize the performance, safety and durability required by airlines Development has been promoted to do. Alan Epstein, vice president of technology and environment at the company said, "This is the opposite of Silicon Valley type innovation because Silicon Valley residents have about 3 years to concentrate," a completely different span I will tell you how things have been advanced.

◆ 30 years of development and future prospects
It is said that P & W's GTF engine began to take shape for the first time around 1988. As mentioned above, in order to realize a GTF engine capable of producing thrust efficiently by rotating a large fan at a low speed, it was necessary to incorporate a special mechanism that has never existed before. The solution that aimed at 28-year-old Michael McCune who was in charge of development was the mechanism of "Turbo Prop" used in propeller aircraft.

In terms of transmitting the rotational force created by the jet engine to the propeller through the gear, both Turboprop and GTF engine are the same way of thinking, and it is natural that the aim was set for the turbo prop mechanism already in practical use I can say However, the big challenge here was that it was a problem of the size and weight of the gear which is very different from the turboprop.

ByMOtty

The gear required for the GTF engine has a caliber of 50 cm and its weight exceeds 100 kg too much. In this class, the technology required to realize rigidity and durability is very high. To increase durability, simply changing the compounding ratio of the alloy will increase the weight and can not achieve the required performance. In the team of Mr. McConn et al., While firmly fixing the gear to be attached to the fan side, we succeeded in realizing the predetermined performance by giving a certain "play" to the gear on the turbine / shaft side is.

In addition to this, P & amp; W is a parent companyUnited TechnologiesHelicopter Manufacturer under umbrella ·Sikorsky · AircraftTurbine engine technology from brothers company Pratt & Whitney Canada and well-established bearings manufacturers established for over 100 yearsTimkenIt is said that we have been developing the GTF engine under the cooperation of various fields, such as receiving bearing technology and further experimenting with wind tunnel equipment in cooperation with NASA.

ByCal Poly Space Systems

P & amp; W which seems to have allowed such a long-term project, but still strict eyes from management have been directed. Mr. Epstein said, "Sometimes I spent a lot of money. In order not to realize that I was investing in projects, I hid a macheune in an inconspicuous manner, so that I could eat from the back of the curtain I was sneakingly giving money to him. "I looked back at the time with a joke.

In 2008 the test prototype will be completed. The development team destroyed such prototypes one after another with tests, repeated the experiments for identifying the problems and realizing performance and safety. Ernest Alvai of AirInsight, a consulting firm in the aerospace industry, said, "There were many wrong first steps, but there were concepts that worked properly in their heads.I am a research that they have accomplished I am amazed at the outcome and the result, they are all winners. "

ByPW 1000 G

Mr. Epstein has always been trusting Mr. McCune's work, and the number of technical patents in the name of Mr. McCune, which is actually 66, proves the result. Mr. Epstein said, "Mike has praised the work that everyone thinks impossible," he also praised.

Although it is a GTF engine that cleared the challenge with such a high technical force, George Ferguson, a senior analyst at Bloomberg Intelligence on the other hand, missed the possibility of mounting on a larger size wide body machine The problem is pointed out. Also, I will talk about the problem that Boeing's next generation narrow body machine, 737 Max does not correspond. The 737 fuselage has lower wing attachment position compared with the same class fighter, so it will not be possible to mount it because PW1000G with relatively large caliber will cause problems such as interference with the ground.

Nevertheless, the PW 1000 G has an engine adoption rate of Airbus · A 320 no shouldering 46% against 54% of General Electric, furthermore an engine exclusively adopted by aircraft such as Bombardier, Embraer, Mitsubishi MRJ The result is such as becoming. The market competition of aircraft engines will continue to change with a span of ten years. About future prospects G. Gregory Hayes, CEO of United Technologies, said, "From a long-term perspective, we have a good impression on the current standing position" from the early 2015 that P & amp; W It is interesting to see how the future development of the GTF engine put into the market will become.

ByMitsubishi Heavy Industries, Ltd.