The paper presents generic simulation procedures for air-planes and aero-engines to support in-flight exhaust emission studies. They take a detailed account of the vehicle aerodynamics and performance as well as engine performance during typical flight missions. The procedures are coupled via lookup tables containing engine data for standard thrust settings. The models and their applicability to emission analysis were tested in a case study for a long-haul airliner with two large turbofans. The Boeing Method 2 fuel flow methodology [1] was selected as a test pollutants model. CO2 and H2O were found by directly linking them to the fuel flow via constant emission indexes. The case study first proved the accuracy of the airplane and engine models by matching available validation data. Secondly, it demonstrated the possibilities of evaluating exhaust emissions at different segments of a flight mission. Both emission profiles and the cumulative environmental footprint of the mission were estimated. The paper concludes by applying the models for the analysis of engine exhaust under varying flight conditions and engine deterioration. This can be used as a tool for optimizing operational procedures for emission reduction and assessing the environmental performance of an aging fleet.

The paper illustrates an aero-engine exhaust emission study, which involves successive simulation procedures for aircraft flight, engine, combustor operation and exhaust emissions. It reveals a generic approach to analyze the effect of changes in flight conditions, power settings and combustor parameters on exhaust gas composition. Using reference measurement data at given engine operating points, pollutant models can be tuned to predict absolute concentration values at altered conditions. Emission formation processes were analyzed in the study using multi-reactor combustor models. The so-called principal pollutants of NOx, UHC, CO and soot were modeled over a broad range of engine power settings at static sea-level conditions. Modeling results were benchmarked against and tuned to emission certification data for a large commercial turbofan. CFD methods were employed to cross-check solution procedures for the engine combustor at the design operating point. Pollutants were also simulated in cruse conditions. Different flight conditions were considered using cross-linked engine and aircraft performance models.

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