A Research On Full States Performance Model For Civil High Bypass Turbofan Engine

Under the background of domestic commercial and technical requirements,as well as the lack of research on engine low speed operation conditions,such as windmilling,ground and altitude starting,this paper built a numerical model and developed an object oriented program to simulate the full states performance for high bypass turbofan engine,Firstly,this paper analyzed the different characteristics of rotating components in full states operation conditions,compared several different extention methods for compressor and turbine maps,developed an extension parametric representation method for compressor and turbine maps based on the minimum loss at component backbone point.Taking a compressor and a turbine maps as examples,the maps were converted and extended.The coverted and extended results were according to the aerodynamic laws.The changes of mechanical loss and characteristics of duct components were also discussed in this part.Secondly,a full states performance model for civil high bypass turbofan engine was built.In order to improve the accuracy of engine transient simulation results,a component volume effect model consisted of mass,energy and momentum conservation was built.Using the model,the differences of several volume effect models and the influences of component volume effect on the engine transient performance were studied.The calculation results showed the influences of different components' volume effects on the engine transient performance were depended on the component's relative position to the turbine inlet section,and the component volume effects had little impacts on high bypass engine transient performance,which means it can be neglected.An extention definition space method was established to solve the problem of meaningless component operating point during engine performance simulation.A particle swarm optimization algorithm with two layers multi-swarms(TLMS Method)was proposed for initial value determination of Newton-Raphson methods.The results showed the TLMS has improved the convergence of engine performance simulation at low speed.An extensible and widely used object-oriented model of high bypass turbofan engine performance model was developed based on analysis of aerodynamic and thermodynamic process of engine components.The performance of CF34-10 A engine was simulated by the model,and the results were varified.The comparison results showed the maximum errors between simulation results and reference data were less than 4% at steady states above idle speed,and the errors were less than 5% at windmilling state.Finally,the engine performance at ground starting,windmilling and altitude relight was simulated using the engine full states performance model.The results of ground starting showed the altitude and ambient temperature had little influences on the fan operation line,the compressor operation line moved closer to the surge boundary as the ambient temperature decreased or the pressure altitude increased.The results of windmilling state indicated that the windmilling speed increased with the increment of flight Mach number.Meanwhile the flight Mach number only had greater impacts on the fan operation line.The altitude relight simulation results showed after ignition,fan operation line moved far away from the surge boundary and the operation line of LPC and HPC moved closer to the surge boundary.At the beginning of APU auxiliary starting process,the high pressure shaft speed increased rapidly while the low pressure shaft speed remained unchanged,and the fan mass flow rate decreased along the speed line in the map.