Effects of intercooling and recuperation on turbofan engine performance
An overall performance simulation model of the intercooled recuperative aero-engine was built, and an overall performance simulation program was developed. Then, analysis of the effects of intercooling and recuperation on the thermodynamic cycle parameters and performance parameters of the turbofan engine can be carried out. The result indicates that the turbofan engine performance can be improved with the proper use of intercooling and recuperation. With the same thermodynamic cycle parameters, the thermal efficiency and the net thrust is larger, while the specific fuel consumption is lower. To gain the same performance, lower overall pressure ratio and lower bypass ratio can be chosen for the intercooled recuperative aero-engine.
Preliminary analysis of thermodynamic cycle of an intercooled recuperated turbofan engine
Intercooled recuperated aero-engine(IRA) is built based on conventional engine while intercooled and recuperated cycles are incorporated.It can utilize effectively engine's heat,improve the thermal efficiency and reduce the specific fuel consumption.The intercooled recuperated aero engine presents a new concept about "green" engine.On the MATLAB platform,an overall performance simulation model has been developed on the intercooled recuperated tri-spool turbofan engine with split exhaust.Then,performance simulation and thermal cycle analysis was carried out under this model.The result indicates that,with the same thermal cycle parameters and specific thrust,the specific fuel consumption of the IRA is less than that of the conventional turbofan engine.
1997 Best Paper Award—Controls and Diagnostics Committee: Active Stabilization of Rotating Stall and Surge in a Transonic Single-Stage Axial Compressor
Rotating stall and surge have been stabilized in a transonic single-stage axial compressor using active feedback control. The control strategy is to sense upstream wall static pressure patterns and feed back the signal to an annular array of twelve separately modulated air injectors. At tip relative Mach numbers of 1.0 and 1.5 the control achieved 11 and 3.5 percent reductions in stalling mass flow, respectively, with injection adding 3.6 percent of the design compressor mass flow. The aerodynamic effects of the injection have also been examined. At a tip Mach number, M tip , of 1.0, the stall inception dynamics and effective active control strategies are similar to results for low-speed axial compressors. The range extension was achieved by individually damping the first and second spatial harmonics of the prestall perturbations using constant gain feedback. At a M tip of 1.5 (design rotor speed), the prestall dynamics are different than at the lower speed. Both one-dimensional (surge) and two-dimensional (rotating stall) perturbations needed to be stabilized to increase the compressor operating range. At design speed, the instability was initiated by approximately ten rotor revolutions of rotating stall followed by classic surge cycles. In accord with the results from a compressible stall inception analysis, the zeroth, first, and second spatial harmonics each include more than one lightly damped mode, which can grow into the large amplitude instability. Forced response testing identified several modes traveling up to 150 percent of rotor speed for the first three spatial harmonics; simple constant gain control cannot damp all of these modes and thus cannot stabilize the compressor a this speed. A dynamic, model-based robust controller was therefore us to stabilize the multiple modes that co prise the first three harmonic perturbations in this transonic region of operation.