Performance of the Clean Exhaust Engine Concept

Abstract

The climatic effects of air-traffic pollutants, such as carbon dioxide (CO2) and mononitrogen oxides (NOx), aerosols, contrails, and aviation induced cirrus clouds, are repeatedly stressed in assessment reports. It is therefore desired to reduce all aviation emissions simultaneously. In this paper, a novel propulsion concept, which has the potential to reduce all pollutants, is assessed regarding its performance. It is based on gas turbine technology, derived from the intercooled and recuperated engine cycle. Exhaust water condensation is facilitated inside the engine to avoid the formation of contrails. Particles and aerosols are scavenged from the exhaust gases during condensation. The condensed water is partially redirected into the combustion chamber to mitigate NOx emissions via water injection technique. Calculations suggest that this new concept allows higher thermal efficiencies than conventional designs, yielding in better fuel economy and hence reduces greenhouse gas emissions. The corresponding design parameters for bypass ratio and fan pressure ratio suggest that this concept might be well suited for propfans or remotely driven fans.