Understanding Thermo-Mechanical Fatigue

Description

Turbine housings have a difficult life. The exhaust gases passing through them may be over 700°C, whereas the surrounding air is only around 90°C giving a thermal gradient across the turbine housing walls. However, at low engine powers, the exhaust gas is much cooler giving a temperature range of 600°C during some duty cycles. It is this cycling of exhaust temperature that incurs stresses in the turbine housing, which must be carefully considered at the design stage.