AN APPROACH TO PERFORMANCE SIMULATION OF VARIABLE CONFLUENCE TURBOFAN FOR FUTURE SUPERSONIC CIVIL AIRCRAFT IN MULTI FIDELITY DISTRIBUTED ENVIRONMENT

摘要

The Conventional Variable Cycle turbofan (CCV) is the one among the most promising propulsion system concepts for future supersonic civil aircraft which should be economically viable and environmentally friendly. This engine concept offers one of the best noise/performance compromises for recent aircraft projects with noise objectives of today and cruise Mach number around 1.6-1.8. Variable area mixer (variable confluence) will allow controlling jet velocity as required at takeoff for noise and in cruise and transonic for performance. A particular advantage of the CCV is that it can be optimized by control of airflow scheduling between different flight conditions which translates in better installed characteristics [1, 2]. SNECMA has systematically evaluated this concept in its recent studies of propulsion systems for supersonic projects, especially for Dassault Aviation in the frame of a program financially supported by French government. SNECMA has been also a main contributor to the choice of the CCV as one of the concepts to be studied in the HISAC (Environmentally Friendly High Speed Aircraft) program. This paper presents recent work on a whole engine simulation with emphasis on the most possible accurate prediction of the variable cycle engine performance. The work is a part of a program that has being conducted for last decades with aim to develop methodology and tools to be capable of analyzing a propulsion system in sufficient detail to resolve effects of multidisciplinary processes and component interactions [3,4]. During past decades some attempts were undertaken in aero engine community to develop high resolution whole engine simulation environment that can meet challenges of 21 century. Such attractive tool should shorten the increasing gap in model fidelity between high resolution component modeling tools such as CFD and FEM models and old fashioned whole engine simulation based on tabulated component maps. This provides more reliable engine computer presentation in a whole range of operation environment at as early as possible stage of engine development [5, 6, 7].