Conceptual design study of a geared turbofan and an open rotor aero engine with intercooled recuperated core

Abstract

The development of more efficient aero engines is becoming a matter of great importance due to the need for pollutant emissions reduction (e.g. CO2, NOx). Toward this direction, two of the most promising aero engine architectures that have been proposed are the ultrahigh by-pass geared turbofan and the open rotor configurations, both of which are targeting the low thrust-specific fuel consumption and reduced NOx production. In the current study, investigations are performed in order to determine the improvements in thrust-specific fuel consumption for these configurations. More specifically, on the basic geared turbofan and open rotor configurations an intercooler and a recuperator are implemented between the compressors and the exhaust nozzle, respectively. The intercooler is installed in order to reduce the high pressure compressor work demand, while the recuperator is used in order to preheat the compressor discharge air by exploiting the otherwise wasted increased enthalpy content of the exhaust hot gas. The recuperator consists of elliptically profiled tubes and its design is based on the innovative tubular heat exchanger core arrangement that has been invented and developed by MTU Aero engines AG. The intercooled recuperative geared turbofan is evaluated against a nonintercooled recuperative geared turbofan, while the intercooled recuperative open rotor is evaluated against a nonintercooled recuperative open rotor. The results showed that the implementation of intercoolers and recuperators can further improve specific fuel consumption and can also lead to NOx emission reduction.