Research On Steady-State Modeling And Correction Technology For Civil Aviation High-bypass Ration Turbofan Engine

The engine control system,as the "brain" of the engine,is especially important in the research of the turbofan engine technology.The engine control system directly determines whether the engine can operate safely and efficiently.Studying of engine control system,which must be based on good mathematical model,the model is the more perfect,the accuracy of the engine control system is the better,the potential is the greater.The control system is good or not which is directly related with the safety of the engine performance and the whole aircraft safety.In this paper,a series of simulation models are established and studied for CFM56-7B large bypass turbofan engine,includes:On the basis of the CFM56-7B turbofan engine,modeling the constant specific heat model and the varying specific heat model of the design point by VC++,then calculated the performance of the design point.On the bias of Gasturb software simulation platform,the design point performance was calculated.Comparaed to two kinds of calculation methods,the result showed variable specific heat computation method was more suitable and more accurate for modeling,in addition to the individual error parameters,the calculation error of model is less than ±2%,the effect is good,the model is feasible and reliable.On the basis of the GE90-85 B turbofan engine,the general analysis of modeling was satisfyed.On the basis of the civil aviation big bypass ratio turbofan engine CFM56-7B,using VC++ to build the single gas flow calculation model and the engine steady state calculation model.On the study of the solving method of steady-state model and calculating the initial guess value,the model showed that all the points are converged,The steady-state model used the component characteristic method and applies the normalization method to the model.Comparaed to the result of steady state model and the model design value,the calculation error of model is less than ±0.2%,the effect is good.Using the steady state control law to keep the NL unchanged,by reducing the efficiency of model parts to get the results of sensitivity analysis,the effect is good,accords with the engine performance,compared with the CFM56-7B sensitive results from CFMI,reached satisfyed results.Aimed to the research on the steady-state model of CFM56-7B engine modification technology,ICM influence coefficient matrix in model was introduced and analyzed in this paper,modeling the engine correction model,the calculation model result is converged.Through the experimental data,selecting the appropriate initial guess value,the results of the modified parameters are more reasonable,which further proved the feasibility of the modified model.