Determination of the modern marine single shaft gas turbine rotor blades fatigue strength parameters

Abstract

Abstract In this paper the problem of the gas turbine blades equivalent dynamic stresses and lifetime determination has been studied. The obtained numerical results have been experimentally verified. The equivalent stresses and the lifetime have been determined for the most dangerous forced vibration bending and torsion modes of all three impellers, forming the turbine rotor. The marine gas turbine engine should be as compact as possible. Thus its rotor consists only of three impellers, that causes rather high vibration and thermal loads on the rotor blades. The lowest number of cycles before the blades failure have been observed for blades of the first impeller, that are influenced by the strongest thermal and vibration loads. Obtained results show that for the surface temperature of nearly 1,000 °C the maximum equivalent stresses are approximately equal to the blade material endurance limit. All numerical results are in good correlation with the experimental data, the divergence is less than 7 %. Received results can be used for the next stage of studies, concerning the rotor creep and fatigue crack problems.