Investigating the emissions and performance of high bypass ratio aero-engines

Abstract

Abstract

In the last decades the development of new technologies and methods of analysis has brought a continuous improvement of the performance of aeronautical jet engines among which are reductions of polluting substances and noise. In this vein, and in accordance with the general attention given environmental issues by the scientific community and governments, a first analysis has been conducted to assess the potential of new types of engines to meet the green environmental expectations. The objects of the study are two powerplants, one with bypass ratio (BPR) 5, used as baseline, and the other with BPR 12. A parametric analysis of the performance and the emissions of these engines was performed using software which directly coupled models of engine performance, emissions, and aircraft operations. Design-point (take-off) and off-design (whole of flight-mission) cases have been considered in order to show the different scenarios and information they could present. Lefebvre equations were used and calibrated to match reasonably the measured NO _x and CO emissions of current combustors. Calibration method and errors are presented to clarify the approach. Trends of NO _x and CO₂ emissions relative to different operating parameters are presented for both cases. The principal differences in emissions for engines of high BPR are shown to be higher values of NO _x associated with the off-design case.