The jet engine rotor is a rotating spool which turns airfoils-containing disks around at high speed. It compresses incoming air from the air intake and converts the hot gas flow from the combustion chamber into mechanical shaft power, called torque. Thus, the rotor of a jet engine is essentially composed of two parts: the compressor and the turbine, both sharing the same shaft or spool. Therefore, the rotor is the fundamental part in an axial-flow type engine. In AC power generation, a jet engine rotor spool is attached to a generator rotor shaft, driving it around at high speed in the stator to generate AC electricity.
Function
The main functions of a jet engine rotor structure are airfoil retention, air compression, torque transmission, and provision of inner flow path surface. The rotor structure must be capable of withstanding the centrifugal forces from the rotor mass inertia which results from the high speed rotation. Beside these mechanical functions, the rotor must satisfy aero-mechanical design requirements as well. Geometrically, the rotor parts are axisymmetric structures, which consist of a combination of airfoils-containing disks, shafts, spacers, and rotating seals.
In most jet engine rotors, the performance requirements dictate the number of airfoil stages needed, which in turn dictate the number of corresponding number of disks. Rotors are supported from the static frames by bearings and shafts. Long rotor spools must be supported at both ends due to system dynamics and flight maneuver loads. Rotors, such as the one in the General Electric CF6-80C2 turbofan engine, are cantilever design with bearings at only one end of the rotor.
Below, a picture of a turbojet engine shows the rotor, with its two essential parts: the axial flow compressor and the turbine, sharing the same spool, or shaft. You can see that the compressor is separated from the turbine by the can-type combustion chamber.
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