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Control & Robotics Lab. Simulation of an INVERSE JET ENGINE MODEL for performance prediction and fault diagnosis in transient operation. Project by Inbal Srebro Levin Dmitry. Supervisor Dr. Michael Lichtsinder. Motivation.
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Control & Robotics Lab Simulation of an INVERSE JET ENGINE MODEL for performance prediction and fault diagnosis in transient operation Project byInbal Srebro Levin Dmitry SupervisorDr. Michael Lichtsinder
Motivation • finding a new and cheaper way to constructing engine maps • Finding a faster algorithm to simulate engine – as a first step towards real time simulation • Proving the model is sensitive to error, as a first step towards error detection algorithm
Objectives • Development of the Inverse Engine Model (IEM) Our goal is to evaluate the engine maps when not all the effective (realistic) map componentsare known: Compressor-Nozzle IEM, Turbine-Nozzle IEM • Evaluation of Turbine/Compressor Map Each turbine/compressor in an engine has an operating map. Complete maps are based on experimental data or predicted by special computer programs. Our goal is to write the program which will be able to predict operating maps. • Fast simulation (and control) Using IEM algorithm to produce MATLAB simulation instrument for map evaluation
Turbine map Each turbine/compressor in an engine has an operating map. Complete maps are based on experimental data or predicted by special computer programs The typical turbine map is shown in the picture below. The x-axis of the turbine map is pressure ratio(PR). The other axis is the corrected flow and the z-axis is efficiency : Evaluated points from data Lines of
Inverse Engine Model (IEM) Command: Program Output: Inverse Engine Model Evaluation of effective engine component maps
CN-Shortened Inverse Engine Model (without Turbine Map) Closed Loop Engine CN-Inverse Model Maps: Compressor+Nozzle
Inverse jet Engine Model VALin n VALout MAPin n MAPout Conditions for construction(short Inverse Model) For CN short Inverse Model:
Advantages of IEM • May be built when not all engine components can be measured • CPU time decrease compare to conventional model • May be used for fast calculation of steady-state and transient performance of single spool engine, and is a step towards real time simulation
Simulation results: Input Input to engine (command) Measure data from transducer
Simulation result:Turbine map Data from full conventional model Evaluated data Two dimensional plot of turbine map, with original contour lines (got from the manufactory)
3D-graphs: Turbine map The slices
Evaluation of Turbine Map (Using Compressor and Nozzle maps)
Evaluation of Turbine Map (Using Compressor and Nozzle maps) mdot4cor 2500 2750 3000 3250 Evaluated data by Inverse engine model Pi45
Evaluation of Turbine Map (Using Compressor and Nozzle maps)
Evaluation of Turbine Map (Using Compressor and Nozzle maps) known data from full turbine map 2750 2500 3000 Evaluated data by Inverse engine model
Evaluation of Compressor Map Compressor Map Data Matrix (1500X4):
Sensitivity to bias error In future development, this model will be used for engine error diagnosis – and for that purpose it has to be sensitive to error: a small error in input should produce larger error in output. Assuming that single transducer faults could be present in the engine at any instance, let’s insert the following fault into the model: measurement bias of +1% for the fault transducer
Evaluation of Turbine parameters:bias error: +1% Error in sensor T05
Conclusions • Shortened Inverse Engine Models can be used for engine component map evaluation using data acquisition during transient (or steady state) operation. • The investigation shows that relatively small measured bias in the inverse model input leads to relatively significant output errors - Sensitivity. • Only one strategy of evaluation is described. However, alternative shortened inverse engine models may be developed for different engine component map detection. Limitations: • Accuracy of the engine model • Measurement error (random and bias) problem
Conclusions (Evaluation of Turbine Map) The idea of evaluating compressor/turbine map which was described above is claimed. By evaluating the compressor or/and turbine map from inverse engine model(IEM) the data which before can be only given by the producer (got from long-lasting and very expensive experiments) of the engine can now be evaluated by just one computer and impressively short time.
Future Tasks • Flexibility One flexible program for all Partly map simulations • Noise in the system – modeling Updating system for being Noise Resistant