What is meant by "thermal stress" in the context of power engineering?

Thermal stress refers to the stress that occurs within materials due to temperature changes, specifically when there are temperature differentials within or across the material. In power engineering, components like pipes, boilers, and turbines often experience significant temperature variations as they operate, resulting in different expansion or contraction rates in different areas. This differential expansion can lead to internal stresses that may cause deformation, fatigue, or failure of the material over time if not properly managed.

Understanding thermal stress is crucial in design and operational practices to ensure that equipment can withstand the stresses induced by temperature changes. Engineers utilize various techniques, such as selecting appropriate materials and providing sufficient expansion joints, to accommodate these stresses in the design of power systems.