Virtual Power Extraction Method of Designing Acceleration and Deceleration Control Law of Turbofan

A new method - virtual power extraction method (VPEM) which is a simple and rapid design tool of optimal acceleration and deceleration control law of two-spool turbofan engine is proposed in this paper. Based on steady-state performance computing model, virtual power extractions from fan shaft and compressor shaft are introduced to make the steady-state operating points (line) move from the normal operating points (line) at the constant corrected line of compressor, with the speeds of fan shaft and compressor shaft maintained at given values. The acceleration and deceleration control law of turbofan can be designed rapidly and accurately in appropriate form, taking surge margin limit of compressor and fan, total temperature limit of turbine inlet and the flameout limit of combustor into account. The computing results of the improved acceleration control law of some turbofan engine indicate that the VPEM is accurate and effective. VPEM is also appropriated for starting control law design of turbofan engine.