Components of jet engines

This article briefly describes the components and systems found in jet engines.

Major components of a turbojet including references to turbofans, turboprops and turboshafts:

The various components named above have constraints on how they are put together to generate the most efficiency or performance. The performance and efficiency of an engine can never be taken in isolation; for example fuel/distance efficiency of a supersonic jet engine maximises at about Mach 2, whereas the drag for the vehicle carrying it is increasing as a square law and has much extra drag in the transonic region. The highest fuel efficiency for the overall vehicle is thus typically at Mach ~0.85.

For the engine optimisation for its intended use, important here is air intake design, overall size, number of compressor stages (sets of blades), fuel type, number of exhaust stages, metallurgy of components, amount of bypass air used, where the bypass air is introduced, and many other factors. For instance, let us consider design of the air intake.

The air intake can be designed to be part of the fuselage of the aircraft (Corsair A-7, Dassault Mirage III, General Dynamics F-16 Fighting Falcon, nose located North American F-86 Sabre and Mikoyan-Gurevich MiG-21) or part of the nacelle (Grumman F-14 Tomcat, McDonnell Douglas F-15 Eagle, Sukhoi Su-27, Sukhoi PakFa, Lockheed SR-71 Blackbird, Boeing 737, 747, Airbus A380). Intakes are more commonly referred to as inlets in the U.S.A.

Pitot intakes are the dominant type for subsonic applications. A subsonic pitot inlet is little more than a tube with an aerodynamic fairing around it.

At zero airspeed (i.e., rest), air approaches the intake from a multitude of directions: from directly ahead, radially, or even from behind the plane of the intake lip.

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