Environmental impact of an aircraft engine with exergo-life cycle assessment on dynamic flight

Abstract

The one of ways to moderat aviation emissions resulting from aircraft engines is to comprehend formation mechanism of environmental impacts. In this article, exergo-environmental aspects of Boeing-747 propulsion system (PW4000 turbofan) used in long range air transport is dealt with life cycle assesment method for eight different flight phases. Environmental impact regarding the turbofan engine and its components is calculated using Eco-indicator points per unit second (Pts/s). Results show that environmental impact related to exergy destruction for the combustor changes from 8.16 mPts/s (at cruise phase) to 24.35 mPts/s at (take-off phase), whereas its environmental impact related to component production and maintenance phases is found as 0.374 mPts/s. On the other hand, exergo-environmental factor of the whole PW4000 engine is calculated as the lowest with 15.83% and 17.22% at take off and climb-out phases, respectively. Moreover, a new environmental indicator, namely, specific thrust environmental effect index (mPts/kN.s) is defined in this study. In this context, environmental effect index of Fan and core specific thrust is estimated the lowest with 0.065 mPts/kN.s and 0.107 mPts/kN.s at cruise phase, respectively. Especially, take-off and climb out phases seem to be the two where the PW4000 behaviour affects environmental effect to the greatest degree. The reason for this could be attributed that these two phases have relatively higher thrust settings. However, considering cumulative environmental impact, cruise phase has the highest environmental impact from exhaust air of the Fan and core as 54.2 Pts and 74.41 Pts, respectively. Consequently, it is expected that the method used in present study could help comparing aircraft flight phases in terms of exergo based-environmental impact.