What does the term "casing" refer to in the context of a gas turbine engine?

In the context of a gas turbine engine, the term "casing" refers to the outer shell that provides structure. The casing serves several important functions, including protecting the internal components of the engine from external elements and maintaining the structural integrity of the engine. It is designed to withstand the high pressures and temperatures that occur during operation, helping to contain the combustion process and the high-speed gas flows that are characteristic of turbine operation.

The casing also plays a critical role in supporting other engine components and providing a pathway for airflow as it moves through the engine stages, such as compression, combustion, and expansion. This structural element is crucial to ensure the engine operates effectively and safely, allowing for proper assembly and integration of other parts such as compressors and turbines within the overall design.