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A REAL-TIME SIMULATOR OF A TURBOFAN ENGINE Jonathan S. LItt Propulsion Directorate U.S. Army Aviation Research and Technology Activity - AVSCOM Lewis Research Center Cleveland, Ohio 44135 and John C. DeLaat and Walter C. Merrill National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohio 44135 O0 ! L_ SUMMARY A real-time dlgital simulator of a Pratt and Whitney FIOO engine has been developed for real-time code verification and for actuator diagnosls during full-scale engine testing. This self-contained unit can operate In an openloop stand-alone mode or as part of a closed-loop control system. It can also be used for control system design and development. Tests conducted in conjunction with the NASA Advanced Detection, Isolation, and Accommodation program show that the simulator Is a valuable tool for real-time code verification and as a real-tlme actuator slmulator for actuator Fault diagnosis. Although currently a small perturbation model, advances in microprocessor hardware should allow the simulator to evolve into a real-tlme, full-envelope, full engine simulation. INTRODUCTION The FIOO engine simulator was designed to support the Advanced Detection Isolation and Accommodation (ADIA) FIOO englne test. The objective of the ADIA engine test was to demonstrate the application of analytical redundancy to the detection, isolation, and accommodation of englne sensor failures (ref. l). That is, to show that the engine can continue to be controlled accurately - even during transients - with one or more of the engine sensors giving false readlngs. The obJectlve of this engine test was also to demonstrate that the ADIA software works on a real engine and is, therefore, reliable and useful in a real environment. This software had already been successfully tested on a hybrid computer simulation of the engine (ref. 2). Due to the usual uncertainties associated with a full scale engine test, it was determined that should changes to the control computer's software be necessary, a simulation of the englne would be requlred for software verlflcatlon. The simulator which has been developed is a portable box which could be taken into the Propulsion Systems Laboratory (PSL) to verify any changes in the control interface and monitoring (CIM) unit's (ref. 3) software before the CIM unit was used to control the engine. The slmulator was installed in the PSL as shown in flgure I. Swapping a patch panel allows the CIM unit to control either the engine or the simulator. This change Is completely transparent to the CIM unlt. This technlque m|nlmlzes rlsk to the engine whlch mlght otherwise occur if the controller's software contains a serious error. The FIO0 engine is a high performance, twin-spool, low by-pass ratio, turbofan engine. Figure 2 shows the locations of the englne Inputs which are defined In table I. Figure 3 shows the locations of the engine sensors defined, along with the other simulator outputs, In table II. The simulator Is based upon a HYTESS-like model (refs. 4 and 5) of the FIO0 englne wlthout augmentatlon (afterburnlng). HYTESS Is a slmplifled FORTRAN slmulation of a generalized turbofan engine. To create the slmulator, the orlginal HYTESS code was revised to incorporate FIO0 specific parameters. Additionally, the executive was adapted from that of the ADIA code (ref. 6) which executes in the ClM unit. This report describes the design and implementation of the FIO0 real-time portable englne simulator. The report discusses the simplified englne model and the actuator and sensor models used In the simulator. Next, the design of the microcomputer implementation, includlng the hardware and software design details, is described. A user's manual Is included with step by step Instructions of how to use the simulator. Performance comparisons with the real englne are presented. Finally, recommendations for future work are given. MODEL The originai full nonlinear simulation of the FIO0 engine is a 13 000 llne FORTRAN program. It incorporates detailed descriptions of both steady-state and dynamlc engine operation throughout the entire flight envelope. This slmulation very accurately reproduces the engine's performance but requlres very large amounts of digital computer memory and processlng time. The HYTESS turbofan engine simulation was developed to provide a structurally simpler alternative to engine simulation and thus reduce computer storage and processing requlrements. Since the main objective of the sfmulatoF is real-time execution, an FIO0 engine simulation with a HYTESS-Iike structure was used. The HYTESS-IIke model www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A_real-time_simulator_of_a_turbofan_engine
