Changing the heat resistance of the turbine blades material with taking into account the influence of operational life

Abstract

The article examines the effect of long-term operational life of a gas turbine engine (GTE) for civil aviation on the durability (heat resistance) of the turbine working blades (WB) material – a foundry heat-resistant alloy ZhS6U-VI on a nickel-based equiaxial structure. The calculation of the static strength of the WB was carried out according to the theory of variable cross-section rods with an initial twist and using the finite element method. The operating time interval from 2400 to 10,500 hours was investigated; the total number of tested samples was 145. A statistical analysis of the test results was performed with the determination of the parameters of the empirical distributions of the value $\lg \tau_{p} $, where $\tau_{p} $ is the heat resistance of the material of the samples from the turbine WB in hours. The law of empirical distributions in each operating time interval is established, the homogeneity of variances $S^{2}$ and averages $\bar{\tau}_{p} $ is checked. Graphs of empirical distributions on normal probabilistic paper are constructed. The influence of operating time on the value of durability $\lg \tau_{p} $ is estimated, an analytical dependence $\lg \tau_{p} =f\left( {\tau_\text{Э} } \right)$ is constructed, where $\tau _\text{Э} $ is the operational time in hours.