Methods of Accelerated Tests of Turbine Blades in Power Plants Operated under Multicomponent Loading Conditions

Abstract

The article presents a method of accelerated tests (ATs) of turbine blades in gas turbine power plants (GTPPs) (aircraft gas turbine engines, gas turbine drives of compressors and electric generators, etc.). It is known that the reliability and service life of GTPPs are mainly determined by the elements of the hot section (the moving blades and nozzle vanes, turbine disks), they are exposed to multicycle loads, repeated static (low-cycle) loads and long-term static loads, as well as to a high temperature gas environment. Gas corrosion is one of the serious types of blade damage which causes a decrease in reliability and efficiency of turbines in GTPPs. The existing methods of ATs of turbine blades which are performed on individual test benches do not reproduce a complete picture of their damage rate, while the ATs of GTPPs reproduce the damage rate of blades caused only by multicycle loads, low-cycle loads and long-term static loads, but they do not reproduce the damage rate caused by the gas environment due to an insignificant duration (as compared to the service life) of the exposure of a blade to a gas environment. Two options of performing blade ATs are examined. The first option consists in testing a blade separately from the GTPP. The blade is subjected to block loading which consists of individual blocks. Each block reproduces in a successive order the damage rate caused by multicycle loads, low-cycle loads and long-term static loads and the damage rate caused by the gas environment. The second option consists in ATs of a GTPP fitted with blades which have already become outdated in terms of corrosion damage rate. The examined methods of blade ATs enable to increase the reliability of the integrated assessment of the robustness of GTPP blades operated under multicomponent loading conditions.