Turbine Disk Life Analysis

The turbine disc is one of the core components of the aeroengine. It is a component used to install and fix turbine blades to transmit power. It works in a high-temperature, high-pressure, and high-speed environment and has extremely high requirements for structural materials. Aeroengines are high-precision technology products. In order to increase the thrust-to-weight ratio of the engines and meet the ever-increasing aircraft performance requirements, their performance parameters are constantly improving. Under this circumstance, the requirements for turbine disc materials continue to increase.
The turbine disk is the top of the six major components of the gas turbine. Its safety and longevity occupy a particularly important position in gas turbines. Turbine disc is circulated
In addition to the limit on the number of times, there is also a limit on service time. People attach great importance to the life of the turbine disk, probably because of the following main reasons:
1.The turbine disc is large in size, heavy in weight and high in speed. The average shear stress of the turbine disk of modern gas turbines at maximum speed has been
increased to 758MPa. Approaches or exceeds the yield strength of many turbine disk materials.
2.The manufacturing quality of the turbine disk is difficult to control. Currently, the turbine discs used in large quantities are forged from a single piece and undergo complex process procedures. To stabilize the quality of each disc, it is necessary to ensure a stable process level in each process. This is difficult to do, especially for some large-scale stocks.
3.During use, the turbine disk undergoes complex changes in medium, temperature and stress. Especially for turbine discs on military engines, this change has random characteristics, which brings great difficulties to the life prediction and control of the turbine disc.
4.After long-term use of turbine disk materials, the structure will deteriorate. The turbine disc materials selected in modern times are generally high-temperature alloys. These alloys are strengthened by metastable second phases and carbides. During long-term use, due to high-temperature stress aging, the second phase will agglomerate and grow, the carbides will change shape, and some will precipitate harmful brittle phases, resulting in an overall decrease in the strength and plasticity of the alloy.
To sum up, we can see a pair of sharp contradictions: on the one hand, because the turbine disk occupies a particularly important position in the gas turbine, people must be able to accurately predict and control its life; on the other hand, because the turbine disk There are many unstable, uncertain, complex and changeable factors in the production and use process, and its lifespan is difficult to predict and control. But it is this pair of contradictions that promotes the continuous and in-depth development of turbine disk life analysis and prediction research work, and also drives the development of related disciplines.