Propulsion directorate/control and engine health management (CEHM): real-time turbofan engine simulation

As the interest in intelligent engine technology increases so does the demand for advanced methods of engine model simulation. Undoubtedly, this element is very cost effective, in that, it can decrease test and experimentation hours significantly. In order to extract more meaningful information for analysis, model simulation must be conducted in a real-time environment. The modular aero-propulsion system simulation (MAPSS) is a generic turbofan engine simulation derived from FORTRAN-based coding developed at NASA Glenn Research Center. It is a non-real time, multi-rate system composed of the controller and actuator dynamics (CAD) and component level model (CLM) modules, representing the digital controller and engine, respectively. This work discusses the implementation and simulation of the MAPSS model in a real-time environment. The controller and engine are loaded on two separate simulators with data transfer between the two systems via a set of electrical cables. This analysis platform encompasses all of the aspects of a real-time environment with plant and sensor noise. The real-time implementation is validated against the non-real time simulation through transient and steady-state conditions. Key parameters of comparison are the three states of the engine, low pressure spool speed (XNL), high pressure spool speed (XNH), and core metal temperature (TMPC), and burner fuel flow (WF36) and net thrust (FN). It is observed with each parameter that the average percent error is less than 1%. Thus, a successful real-time implementation is achieved while maintaining a high degree of accuracy. The model´s behavior now approximates a real gas turbine and provides an ideal test bed for observing faults and failures, engine parameter variations, and degradation over time. This in turn provides a valuable tool in observing the symptoms of failure, developing diagnostics routines, and improving prognostic algorithms.