Research On Modeling Technology For High Bypass Ratio Turbofan Engine

Modeling and simulation of aeroengine is one of the essentials to develop advanced aeroenginecontrol system with lower cost, less time and higher efficiency. For new developed aeroengine, engineperformance simulation model can be used for aeroengine control system digital simulation, hardware-in-the-loop simulation and semi-physical simulation. For on-wing aeroengine, on-board enginemodel can be used to diagnosis, isolate and reconfiguration signals for fault sensors.Aimed at two key potential performance simulation requirements for a twin-spool high bypassratio separate exhaust turbofan engine, the following research work were carried out, includes:To meet the demand of aeroengine control system simulation verification, a full-state, fullenvelop Component Level Model(CLM) for a high bypass ratio turbofan engine was developed,which can simulate steady-state performance, transient performance, as well as startup performanceboth on ground and at a high altitude. In the CLM, the low speed characteristics maps of rotatecomponents were got by using exponential extrapolation method. The heat exchange between hotcomponents and gas were taken into account, as well as the effect of turbine tip clearance variationsand total pressure losses in the duct components. Compared to base data, the calculation error ofsteady-state model is less than2%, and that of transient model is less than5%. In flight envelope,4446points were selected to test the convergence of the model, and results show that all the points areconverged.To meet the demand of signal reconfiguration for gas path sensor in engine digital control system,both steady-state and transient on-board model were built for high bypass ratio turbofan engine. Basedon engine rig test data, a steady state baseline model was built using similarity theory. Compared withrig test data, the signal reconfigured error of on-board steady model is less than2%. Besides, based onhigh bypass ratio turbofan CLM, an on-board transient model was also carried out by simplifiedcomponent calculation and nonlinear equations solving algorithm, etc. Without losing any calculationprecision, the on-board model takes only0.2ms to finish one step calculation in a computer with3.2GHz CPU. It is about10times faster than that before.The full-envelop, full-state turbofan engine component level model carried out in this paper hasbeen applied in different kinds of simulation verifications for high bypass ratio turbofan engine digitalcontrol system.