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GAS-TURBINE ENGINES OF AI-20 FAMILY
GAS-TURBINE ENGINES OF AI-20 FAMILY
Drive engine external view GAS-TURBINE ENGINES OF AI-20 FAMILY
Longitudinal section of drive engine REDUCTION GEAR The gear, located in the front part of the engine, is intended to reduce the number of engine rotor revolutions and transfer the gas turbine excess power to the rotating shaft of synchronous generator. The gear consists of a planetary stage, a gear train stage, an output shaft and a torquemeter mounted in the reduction gear casing cast of magnesium alloy. The engine rotor is coupled to the reduction gear mechanism by means of a drive shaft.
FRONT CASING The casing serves for the power coupling of the compressor with the engine reduction gear. The accessories of the main engine systems and engine-to-engine mount attachment trunnions are attached to the flanges located on the exterior surface of the casing. The drives of accessories, compressor rotor front bearing support and inlet guide vanes assembly are mounted in the front casing chambers.
COMPRESSOR The axial-flow subsonic ten-stage compressor is intended to suck in, compress and deliver the air into the combustion chamber. The drum-and-disk type compressor rotor consists of ten separate disks with the blades fitted to their rims. Disks, rear shaft and compressor rotor blades are made of high quality stainless steel. The compressor casing is a welded structure with a split in the horizontal plane.
The combustion chamber is attached to the rear flange of the compressor casing. The compressor comes to run at the operating speed and operates at lower RPM without surging due to bleeding some amount of air into the atmosphere through special valves. The inefficient air leakage is eliminated by the labyrinth seals fitted between the rotor and stator, thereby increasing compressor efficiency. The constant compressor RPM at the operating power conditions, moderate circumferential speeds and specific design features ensure high reliability of compressor operation during its whole service life. COMBUSTION CHAMBER ASSEMBLY The combustion chamber assembly is the engine load-bearing unit which takes up the turbine weight, forces and moments that emerge in the chamber and turbine during engine operation. The assembly comprises combustion chamber casing, main fuel nozzles (gas burners), flame igniters, fuel manifold and a number of small assemblies. The combustion chamber casing is a welded structure made of stainless steel. The annular type combustion chamber is made of heat-resistant sheet material and provided with ten domes welded to the front ring. The design of combustion chamber ensures ignition and fast flame transfer at starting. The optimum combustion process combined with the effective system of sublayer cooling of walls provide for stable operation of combustion chamber at all power conditions as well as uniform temperature pattern at the turbine inlet and high operational reliability of combustion chamber throughout the entire service life.
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