David Gustafsson, Siemens

Crack Propagation Challenges in Gas Turbine Engine
When May 06, 2015
from 03:00 PM to 04:00 PM
Where LR8, IEB Building, Engineering Science
Contact Name
Contact Phone 01865-613069
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In gas turbines it is important to design for as high gas temperatures as possible in order to attain a high thermal efficiency. In the case of power generating gas turbines, the increase of temperature leads to lower fuel consumption, reduced pollution and thus lower costs. The high-temperature load carrying ability of critical components is therefore one of the most important factors that set the limits in gas turbine design.  Even though high temperature resistant superalloys are used, hot components are usually designed to run near their temperature and load limits. Uncertainties in models and methods used for fatigue life prediction under these circumstances are thus very problematic. 

 

Another complicating factor is the shift in the power generation market more focusing on distributed energy generation for a local energy market compared to the classic focus on lager power plants generating power for a larger geographical area. This is due to the larger part of renewable energy sources, such as wind and solar power, available today. Unfortunately, the wind don’t blow and the sun don’t shine twenty four seven. Thus, a reliable backup solution is needed.  The industrial gas turbine fills this role rather well but this type of operation means that the gas turbine will be forced to start daily which will have a huge impact on component cyclic life.

 

Among the most important questions in gas turbine design today is therefore how to predict the fatigue life of critical components. In many cases designing against fatigue crack initiation is not enough but designers must rely on a damage tolerant design where stable crack growth must be allowed. Component failure is extremely costly and can potentially lead to the loss of human life. Thus, avoiding failure is always a first priority. This put huge demands on accurate crack growth calculation methods and high quality material data

 

This seminar will discuss some of the more difficult challenges related to crack propagation in gas turbine design such as intergranular cracking of gas turbine disc materials, crack growth in single crystal material, complex loading cycles and complex geometries.