Engine Performance

IAR develops and validates methods for estimating engine and component performance for use in acceptance testing, and fault diagnosis. Engine performance analysis and diagnosis is based on analytical models. Aerothermodynamic processes have been modeled at the component level to compare with data acquired during acceptance and development testing. Software tools are the typical means of assembling and delivering the results and for this a generalized analysis package, SPK, has been developed that allows uninstalled and installed performance to be predicted with varying levels of input data.

Some specific modeling problems have been addressed through international civil and military working groups; for example the North Atlantic Treaty Organization's (NATO) Advisory Group for Aerospace Research and Development (AGARD) has studied water ingestion effects. Steady state modeling methods developed by IAR, in partnership with GasTOPS Ltd., produced software packages for the J57, T56, F404 and J85 engines. The simulation procedures were further documented and applied to a requirement for a diagnostic tool by the Turkish Air Force. As well, IAR and collaborators have developed automated estimation tools and neutral network solutions for performance modeling.

Key to the application of the engine models is the validation and tuning to match an actual engine under test. Test, control and analysis methods have been developed at IAR to meet these needs. IAR contracted with GasTOPS and the Canadian Department of National Defence (DND) to gather engine performance characteristics during steady state and transient operation. This data is used to improve the DND F404 model used in on-going engine health monitoring programs at DND bases.

Test and analysis capabilities have been applied to two other DND operational needs. One test and analysis project seeks to reduce fuel costs during engine testing; the other aims for improved criteria for establishing stabilized performance, with a target fuel savings of $100,000 per year. An extensive series of F404 engine tests has provided valuable data for this need and also further improvements to the DND F404 transient model. IAR staff also worked with DND to introduced the real time thrust sensor technology into their flight test operations.

The integration of such modeling and test methods is under study by the graduate studies program at Carleton University in Ottawa. Physical models based on mechanical engineering principles are being combined with system identification methods typical of electrical engineering analyses. The goal is improved transient modeling and prediction for use in fault diagnosis. Contacts with Pratt & Whitney Ltd. have identified applications to the diagnosis of faults in hydro-mechanical fuel controls affecting engine reliability and aircraft availability.