The Gas Turbine Heat Cycle and its Influence on Fuel Efficiency and Emissions

Abstract

This paper discusses the application of heat exchangers to aircraft engines. At first the thermodynamic cycles with and without heat recovery and intercooling will be compared in a parameter study and the most suitable heat cycle for aircraft application will be selected. Next, heat exchangers of different kind and geometry and their off-design behaviour will be described. One of them will be selected for an intercooled and recuperated (ICR) aircraft engine. The results of an engine performance simulation program for this engine will be presented, the simulation will cover several operating points at sea level static (SLS) and in flight. The data base of the simulation corresponds to real engines and heat exchangers and therefore represents today's' technology. The results of the simulation will be compared with data of a modern high-bypass turbofan, which has been simulated by the same program. Finally the behaviour of the intercooled, recuperative and the conventional engine on a flight mission will be compared, which has been calculated by a flight performance program coupled with the engine simulation program. The results will be summarised and evaluated regarding fuel consumption, NOx and soot production as well as weight assumptions.