An analytical method of fatigue damage estimation for compressor stator blades of gas turbines under rotating stall (1st report, residual life assessment of gas turbine compressor blades)

摘要

Compressor stator blades of gas turbines are subjected to severe conditions such as dynamic pressure oscillation due to rotating stall, corrosive operating environments, and a high number of operations. To improve the reliability of such blades, an analytical method for estimating fatigue damage of these blades has been developed. This method is based on blade vibratory-stress analyses, stress peak counting, and use of actual environmental data. The blade-vibratory stress analyses took superposition of multi peaks of the stress spectrum into account. And the numerically simulated stress from these analyses showed better agreement with measured stress than that from a traditional stress analysis, which is based on frequency response analysis considering a single peak of the lowest single eigen vibration mode. Furthermore, the fatigue damage of the blade under rotating stall was estimated by the stress peak counting of synthesized historical stress waves which were given by the blade-stress analyses and from material data.