What is an axial compressor

Axial compressors

Axial compressors

compress the air through multiple sets of star-shaped vanes that are mounted along the engine axis. They were already used in the first series engines manufactured by BMW and Junkers in Germany and are now in common use.


The letters stand for "Component Validator for Environmentally-Friendly Aero-Engine". With this project, the turbine manufacturer MTU demonstrated the feasibility of a recuperative engine or a heat exchanger engine.

Recuperative engine

Jet engine with heat exchanger in the exhaust jet: The heat exchanger conducts heat back into the engine. It is used to preheat air flowing into the combustion chamber so that less kerosene has to be used in the combustion chamber itself. In addition, an intercooler is required upstream of the compressor to prevent the compressor from overheating. The efficiency of a recuperative engine is significantly higher than that of a conventional jet turbine.

Centrifugal compressor

Centrifugal compressors use centrifugal force and direct the air to the outside of the housing wall. From there it flows on into the combustion chamber. The first radial compressors had the advantage of being based on the compressors of piston engines - and thus being able to use tried and tested technology. They are sturdy and easy to build, but they are also large and not particularly efficient. Therefore, their use was given up in the 1960s.

Turbine blade

One of the most important components of a jet engine: The blades sit on ring rings in the compressor, on the one hand in the turbine and on the other in the front of the fan. A distinction is made between movable or rotor blades and fixed or stator blades. Stator blades are stuck in the compressor. Turbine blades are made of very resistant metal alloys and have thin channels inside, in which cooling air circulates. Their production requires up to 50 operations. Centrifugal forces, which correspond to a load of several tons, act on this component during operation.

Bypass ratio

This numerical value indicates the ratio between the hot air flow from the turbine and the cold air flow from the fan. Today's engines have a bypass ratio of 1: 6 to 1: 7. Developers aim for a ratio of 1:10 to 1:12.

March 21, 2006

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