Real-Time Transient Three Spool Turbofan Engine Simulation: A Hybrid Approach

Abstract

This paper presents a transient three-spool turbofan engine simulation model that uses a combination of intercomponent volume and iterative techniques. The engine model runs in real time and has been implemented in MATLAB/SIMULINK environment. The main advantage of this hybrid approach is that it preserves the accuracy of the iterative method while maintaining the simplicity of the intercomponent volume method. The iterative approach is applied at each engine subsystem to solve algebraic thermodynamic equations for exit enthalpy, entropy, and temperature, whereas the intercomponent volume method is used to calculate pressures derivatives and hence pressures at corresponding engine stations. This allows the engine state vector to be updated at each pass through the engine calculations. This technique was applied as a test case on the Rolls Royce Trent 500 three-spool turbofan engine, and the results were compared with an iterative method. As the engine state vector is updated during each cycle, the model lends itself for easy integration into nonlinear aircraft simulations, real-time engine diagnostics/prognostics, and jet engine control applications.