In gas turbine compressors, what does the term "stall" indicate?

The term "stall" in gas turbine compressors specifically refers to the inability of a blade to maintain airflow. This occurs when the airflow separates from the blade surface, leading to a dramatic reduction in pressure and flow through the compressor. It typically happens when the angle of attack exceeds a critical point, causing the compressor to become inefficient and unable to supply the required compression ratio. Stall is a crucial phenomenon in compressor design and operation, as it can lead to operational issues and reduced performance. Understanding stall is vital because it can affect the overall efficiency and reliability of gas turbine engines.