Aircraft performance with onboard water condensed from engine core exhaust for contrail prevention

Abstract

Aviation industry has experienced a constant growth over the last decades, and forecasts suggest that this trend will continue. This is not attractive from an environmental point of view due to the increasing contribution of aviation to Global Warming. Significant research has been done on aircraft emissions. It suggests that the impact of contrails and aircraft induced cirrus formed by water vapour within the engine might be significant enough to be a concern. Consequently, several contrail avoidance strategies have been designed during the last two decades, but they all present the same drawback: a fuel overconsumption. One of these strategies consists in condensing the water vapour within the engine, so that it can be stored on the aircraft or released into the atmosphere in a controlled manner. This technique is the basis of the current work. The aim of this study is to investigate the feasibility of storing water onboard and establish the effects it may have on aircraft performance. To assess the penalties of the technique, an analytical model of the aircraft capable of water storage was developed. Once the penalties were determined, the net balance between the positive effect of contrail prevention and the negative effect of the additionally emitted CO2 is calculated. From these analyses, it was concluded that if contrails are avoided in 2020 a 40-50% reduction in total aviation radiative forcing could be achieved in 2050 due to this contrails prevention technique. However, the water-carrying aircraft experienced a 23.23% range reduction for the same fuel and a 17.35% fuel burn penalty for the same range in comparison to the design point of the baseline aircraft.