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A jet engine is a type of reaction engine, discharging a fast-moving jet of heated gas that generates thrust by jet propulsion. While this broad definition may include rocket, water jet, and hybrid propulsion, the term jet engine typically refers to an internal combustion air-breathing jet engine such as a turbojet, turbofan, ramjet, pulse jet, or scramjet. In general, jet engines are internal combustion engines.
In an internal combustion engine, a turbocharger is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the engine in order to produce more power for a given displacement.
A gas turbine, gas turbine engine, or also known by its old name internal combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part and are, in the direction of flow:
A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a combination of the preceding generation engine technology of the turbojet, and a reference to the additional fan stage added. It consists of a gas turbine engine which achieves mechanical energy from combustion, and a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust.
An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Aircraft using power components are referred to as powered flight. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many small UAVs have used electric motors.
The Rolls-Royce Trent is a family of high-bypass turbofans produced by Rolls-Royce. It continues the three spool architecture of the RB211 with a maximum thrust ranging from 61,900 to 97,000 lbf . Launched as the RB-211-524L in June 1988, the prototype first ran in August 1990. Its first variant is the Trent 700 introduced on the Airbus A330 in March 1995, then the Trent 800 for the Boeing 777 (1996), the Trent 500 for the A340 (2002), the Trent 900 for the A380 (2007), the Trent 1000 for the Boeing 787 (2011), the Trent XWB for the A350 (2015), and the Trent 7000 for the A330neo (2018). It has also marine and industrial variants like the RR MT30.
In aeronautics, a ducted fan is a thrust-generating mechanical fan or propeller mounted within a cylindrical duct or shroud. Other terms include ducted propeller or shrouded propeller. When used in vertical takeoff and landing (VTOL) applications it is also known as a shrouded rotor.
The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core.
A propfan, also called an open rotor engine, open fan engine or unducted fan, is a type of aircraft engine related in concept to both the turboprop and turbofan, but distinct from both. The design is intended to offer the speed and performance of a turbofan, with the fuel economy of a turboprop. A propfan is typically designed with a large number of short, highly twisted blades, similar to the (ducted) fan in a turbofan engine. For this reason, the propfan has been variously described as an "unducted fan" (UDF) or an "ultra-high-bypass (UHB) turbofan".
A turboshaft engine is a form of gas turbine that is optimized to produce shaft horsepower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the exhaust and convert it into output shaft power. They are even more similar to turboprops, with only minor differences, and a single engine is often sold in both forms.
The General Electric CJ805 is a jet engine which was developed by General Electric Aircraft Engines in the late 1950s. It was a civilian version of the J79 and differed only in detail. It was developed in two versions. The basic CJ805-3 was a turbojet and powered the Convair 880 airliner, while CJ805-23, a turbofan derivative, powered the Convair 990 Coronado variant.
The General Electric YF120, internally designated as GE37, was a variable cycle afterburning turbofan engine designed by General Electric Aircraft Engines in the late 1980s and early 1990s for the United States Air Force's Advanced Tactical Fighter (ATF) program. It was designed to produce maximum thrust in the 35,000 lbf (156 kN) class. Prototype engines were installed in the two competing technology demonstrator aircraft, the Lockheed YF-22 and Northrop YF-23.
The geared turbofan is a type of turbofan aircraft engine with a planetary gearbox between the low pressure compressor / turbine and the fan, enabling each to spin at its optimum speed. The benefit of the design is lower fuel consumption and much quieter operation. The drawback is that it increases weight and adds complexity.
Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller. Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems.
The Pratt & Whitney PW1000G, also called the GTF, is a high-bypass geared turbofan engine family produced by Pratt & Whitney. After many demonstrators, the program was launched with the PW1200G on the Mitsubishi SpaceJet in March 2008, first flight tested in July 2008. The first variant to be certified was the PW1500G for the Airbus A220 in February 2013. The program cost is estimated at $10 billion.
The Honeywell/ITEC F124 is a low-bypass turbofan engine derived from the civilian Honeywell TFE731. The F125 is an afterburning version of the engine. The engine began development in the late 1970s for the Republic of China (Taiwan) Air Force AIDC F-CK Indigenous Defence Fighter (IDF), and it first ran in 1979. The F124/F125 engine has since been proposed for use on other aircraft, such as the T-45 Goshawk and the SEPECAT Jaguar, and currently powers the Aero L-159 Alca and the Alenia Aermacchi M-346. The F124 has a rather unusual design for a two spool gas turbine engine, using both axial and centrifugal compressors in its high-pressure compressor. There are currently only three production variants of the engine, although several more have been proposed throughout its lifespan.
A cross-drive steering transmission is a transmission, used in tracked vehicles to allow precise and energy-efficient steering.
On maritime vessels, noise and vibration are not the same but they have the same origin and come in many forms. The methods to handle the related problems are similar, to a certain level, where most shipboard noise problems are reduced by controlling vibration.
The Turbomeca Astafan is a single-spool, variable-pitch turbofan engine developed from the Turbomeca Astazou. Despite successful flight-testing, an efficient, quiet and clean design and some commercial interest, the Astafan never entered series production. The engines were only flown on the Fouga 90 prototype and Turbomeca's two test aircraft.
A variable pitch fan is similar in concept to that of a variable-pitch propeller and involves progressively reducing the pitch of the fan on a turbofan as the engine is throttled. Although variable pitch fans are used in some industrial applications, the focus of this article is on their use in turbofan engines. No production engine uses such a feature; however, it will likely be required on at least some of the next generation of high bypass ratio turbofans.
References
- ↑ Wragg, David W. (1973). A Dictionary of Aviation (first ed.). Osprey. p. 4. ISBN 9780850451634.
- ↑ "World's largest and most efficient aircraft engine aces first tests". New Atlas. 2023-05-22. Retrieved 2023-09-24.
- 1 2 Keil, Christian (February 28, 2024). "Interview with Ian Brooke". x.com.
- ↑ McCormick, Packy (April 1, 2024). "Astro Mechanica". www.notboring.co. Retrieved 2024-04-02.
- ↑ Côté, Andrew (February 28, 2024). "Astro Mechanica". x.com. Retrieved April 2, 2024.