Justification of Program for Accelerated Tests of Aircraft Auxiliary Gas Turbine Engine

Abstract

This article presents a justification of the program for accelerated tests (ATs) of an aircraft auxiliary gas turbine engine (AGTE) which consists of a turbine, a compressor, a combustion chamber, a reduction gearbox, a DC generator (GS-12TO) and an AC generator (GT 4bPCh6), a fan, and other units. The AGTE is designed for air starting of aircraft main engines at aerodromes, for pneumatic supply for the air-driven devices in flight in case of failure of the primary power supply sources, for ensuring the AC and DC power supply for the onboard power system of the aircraft both on ground and in flight. The justification of the program for the ATs is provided with the account taken of the primary elements of the assemblies which determine the reliability and the service life of the AGTE: the nozzle vanes and the blades of the first turbine stage; the disks of the second and third turbine stages; the thrust and radial bearing of the turbocompressor rotor; the driving gear of the reduction gearbox; and the elements of the DC and AC generators. The modes and the duration of the ATs are determined for the longest load step of the AGTE in operation which includes the air bleed at the compressor discharge (G_ab = 1.35 kg/s) and the electric power takeoff from the DC generator (N_{DC gen.} = 12 kW) and the AC generator (N_{AC gen.} = 33 kVA). The modes and the duration of the ATs determined in this article enable us to ensure the equivalence of the ATs and the long-duration tests (LDTs) (the equivalence is understood to be the equality of the damage rates of the primary elements of assemblies during the LDTs and the ATs).