Modeling and simulation of Thermally Unstable stall lIne in turbofan Engines

In low bypass turbofan engines, time to max thrust is a key performance parameter.  This performance parameter is key to successful operating an aircraft during critical maneuvers such as landing aborts and combat maneuvers.  A limiting factor to achieve max thrust is time for the engine to spool to desired speed and is limited by high pressure compressor stall margin.  High pressure compressor stall margin is most stressed during bodie turnaround where the engine is thermally unstable and the actual stall line has moved closer to the operating point.  Historically the thermally stable and unstable stall lines have been identified thru extensive testing in an altitude test cell and acceleration schedules have been made to achieve desired stall margin.  The incorporation of FADEC controls in turbofan engines has enabled for real time modeling and flexible acceleration schedules.  A real time model of the thermally unstable stall line would allow for more aggressive acceleration schedules and decrease time for engine to achieve max thrust.  In recent years more research is being done into stall margin effects driven by tip clearances and heat addition to the gas path.  Using historically test data, I intend to model the thermally unstable stall line and use it to drive an engine control to achieve stall free operation and improved performance in MATLAB.