The different aspects of overall performance of three variable cycle engines (VCE) candidates for future supersonic civil transport are analysed in this work. These aspects concern the design and off-design points performance, the airframe engine integration and variable geometry compressor and turbine design and performance. The three engines are compared to a traditional turbojet. The variable compressor maps were obtained with their running lines for the whole mission profile including the transition mode from medium býpass ratio to a lower bypass ratio turbofan. The specific fuel consumption (SFC) of the VCEs showed a significant improvement, especially at subsonic cruise, relative to a Turbojet engine. The extent of the variable geometry on the compressor stator angles, mixing area and the nozzle throat and exit areas is evaluated. The Fuel bill is estimated for two standard mission profiles. The effect of installation is estimated on an isolated nacelle. A sizing calculation is carried out for the whole nacelle including the intake and the nozzle. The drag due to the friction, pre-entry, afterbody and the shock waves is calculated in order to estimated the installed performance of the three engines. In the search of improving the VCE performance at subsonic cruise, the use of variable geometry at the low pressure turbine for the Turbofan-Turbojet engine is investigated. The effects of varying the LP turbine guide vanes stagger angle on the engine performance and component parameters are analysed. The turbine efficiency and non-dimensional mass flow changes due to the use of variable geometry are estimated. An updated version of the Turbornatch program was corrected and tested in order to study variable cycle engines, especially to simulate the transition from one mode to another.

The different aspects of overall performance of three variable cycle engines(VCE) candidates for future supersonic civil transport are analysed in this work. Theseaspects concern the design and off-design points performance, the airframe engineintegration and variable geometry compressor and turbine design and performance. The three engines are compared to a traditional turbojet. The variablecompressor maps were obtained with their running lines for the whole mission profileincluding the transition mode from medium b?pass ratio to a lower bypass ratio turbofan. The specific fuel consumption (SFC) of the VCEs showed a significant improvement, especially at subsonic cruise, relative to a Turbojet engine. The extent of the variablegeometry on the compressor stator angles, mixing area and the nozzle throat and exitareas is evaluated. The Fuel bill is estimated for two standard mission profiles. The effect of installation is estimated on an isolated nacelle. A sizing calculationis carried out for the whole nacelle including the intake and the nozzle. The drag due tothe friction, pre-entry, afterbody and the shock waves is calculated in order to estimatedthe installed performance of the three engines. In the search of improving the VCE performance at subsonic cruise, the use ofvariable geometry at the low pressure turbine for the Turbofan-Turbojet engine isinvestigated. The effects of varying the LP turbine guide vanes stagger angle on theengine performance and component parameters are analysed. The turbine efficiency andnon-dimensional mass flow changes due to the use of variable geometry are estimated. An updated version of the Turbornatch program was corrected and tested inorder to study variable cycle engines, especially to simulate the transition from one modeto another.

Six of the candidate propulsion systems for the High-Speed Civil Transport are the turbojet, turbine bypass engine, mixed flow turbofan, variable cycle engine, Flade engine, and the inverting flow valve engine. A comparison of these propulsion systems by NASA's Glenn Research Center, paralleling studies within the aircraft industry, is presented. This report describes the Glenn Aeropropulsion Analysis Office's contribution to the High-Speed Research Program's 1993 and 1994 propulsion system selections. A parametric investigation of each propulsion cycle's primary design variables is analytically performed. Performance, weight, and geometric data are calculated for each engine. The resulting engines are then evaluated on two airframer-derived supersonic commercial aircraft for a 5000 nautical mile, Mach 2.4 cruise design mission. The effects of takeoff noise, cruise emissions, and cycle design rules are examined. Berton, Jeffrey J. and Haller, William J. and Senick, Paul F. and Jones, Scott M. and Seidel, Jonathan A. Glenn Research Center NAS3-26617; NAS3-6618; NAS3-25965; NAS3-25963; WBS 22-714-09-46

A comprehensive review of the science and engineering behind future propulsion systems and energy sources in sustainable aviation Future Propulsion Systems and Energy Sources in Sustainable Aviation is a comprehensive reference that offers a review of the science and engineering principles that underpin the concepts of propulsion systems and energy sources in sustainable air transportation. The author, a noted expert in the field, examines the impact of air transportation on the environment and reviews alternative jet fuels, hybrid-electric and nuclear propulsion and power. He also explores modern propulsion for transonic and supersonic-hypersonic aircraft and the impact of propulsion on aircraft design. Climate change is the main driver for the new technology development in sustainable air transportation. The book contains critical review of gas turbine propulsion and aircraft aerodynamics; followed by an insightful presentation of the aviation impact on environment. Future fuels and energy sources are introduced in a separate chapter. Promising technologies in propulsion and energy sources are identified leading to pathways to sustainable aviation. To facilitate the utility of the subject, the book is accompanied by a website that contains illustrations, and equation files. This important book: Contains a comprehensive reference to the science and engineering behind propulsion and power in sustainable air transportation Examines the impact of air transportation on the environment Covers alternative jet fuels and hybrid-electric propulsion and power Discusses modern propulsion for transonic, supersonic and hypersonic aircraft Examines the impact of propulsion system integration on aircraft design Written for engineers, graduate and senior undergraduate students in mechanical and aerospace engineering, Future Propulsion Systems and Energy Sources in Sustainable Aviation explores the future of aviation with a guide to sustainable air transportation that includes alternative jet fuels, hybrid-electric propulsion, all-electric and nuclear propulsion.