This report covers all major steps to establish an aviation emission inventory for 2019. This emission inventory is set up based on four consecutive steps. The first step is to gather all required data in the information model and this also includes some pre-processing of data to make it as complete as possible. The second step is to estimate the point performance of the aircraft at multiple waypoints along the trajectory based on the Base of Aircraft Data (BADA). This also allows for fuel consumption estimation. The third step uses the point performance data to estimate emissions under the respective flight condition. The last step addresses introduced uncertainties based on the different models. From a first principle perspective the uncertainty on a fleet wide scale (and for short and long haul flights) is found concerning the fuel consumption and various emission species (for example nitrogen oxides and carbon monoxide) using a Monte Carlo simulation. The trajectory data is obtained from flightradar24 in which gaps were identified where the type of aircraft, origin airport or destination airport were missing. Complementing of the database is based around the provided flight numbers and call signs. Based on airline data a variety of assumptions is made relating to payload fraction (69%) and increase in flight distance (8%) compared to the great circle distance. The trajectory is estimated using the rate of climb and descent provided in BADA. The emission model then uses constant emission indices, the boeing fuel flow method 2 (BFFM2) and the DLR method to compute all emissions according to: • Constant emission index: carbon dioxide (corrected for emission index of carbon monoxide), water vapor and sulfur oxide. • BFFM2: carbon monoxide, unburned hydrocarbons and nitrogen oxides. • DLR: black carbon emission. The uncertainty analysis, finally, covers airline operational uncertainty, model uncertainty and engine aging uncertainty to find an average increase in fuel consumption of 4.2%. Due to the influence of fuel flow, other emission species are increased with a different fraction. Due to computational limitations it has been decided to analyze one week, which will be representative of the entire year. Based on this analysis an annual fuel consumption of 272 Tg is simulated with corresponding carbon dioxide emission of 857 Tg. In addition, a nitrogen oxide emission of 5.3 Tg is found. All emission species are mainly emitted on the northern hemisphere on three geographical locations: north America, Europe and south-east Asia. The strongest recommendation is to include military flights and non-jet aircraft in the analysis (mainly turboprop aircraft). In addition, to decrease the dependency on data of a single week, it is advised to obtain more computational power to allow for analysis of multiple representative weeks preferably in both ICAO specified seasons. Finally it is recommended to extend the uncertainty analysis to cover more individual uncertainties such as the uncertainty in cruise altitude (based on airline routing) and to find more research on the uncertainty of sulfur content in kerosene.

With an increasing complexity of systems, systematic design space exploration is required for fair analysis and comparison of architecture design options. However, there is still a need for a benchmark problem to support the development & evaluation of optimization algorithms and system architecture design space modeling methods, and to educate stakeholders in system architecture optimization. The thesis focus lies on the creation of such benchmark problem with an application to aircraft jet engine design, which is subsequently tackled by developing an MDO tool using a system architecting approach with mixed-discrete and multi-objective capabilities. The tool was built with the open-source software pyCycle and OpenMDAO and can generate, analyze and compare different aircraft engine architectures on several disciplines including engine thermodynamic cycle analysis, weight, geometry, emissions and noise. Therefore, it is able to tackle the black-box, mixed-discrete, multi-objective and hierarchical nature of system architecture optimization problems.

This study analyses the feasibility of an engine architecture using bypass cooled cooling air as a method for reducing specific fuel consumption of current and future high bypass turbofan engines. As cooled cooling air reduces required turbine cooling massflow, a major source of loss in modern aeroengines, it is believed that the concept can improve engine efficiency. No extensive or explicit study on the merits of this concept has been performed, however. Using the 0-D engine analysis software GSP, engine performance parameters at Take-Off and Cruise, such as, specific fuel consumption and (specific) thrust were evaluated against altering feed cooling air temperature by 0 to -300K and heat exchanger induced pressure losses of 0 to 8% in the bypass. This was done for two test cases; the Leap-1A engine (TOC OPR 50, CRZ BPR 11.1, TO FN 121kN) representing current conventional technology and GTF2050, a geared turbofan engine (TOC OPR 75, CRZ BPR 17.1, TO FN 174kN) with entry into service of 2050. For the Leap-1A engine the specific fuel consumption increased up to 1.9% at cruise and for GTF2050, the increase was up to 4.1%. It is shown that the change in fuel consumption is linear with the decrease in cooling fraction, as for both engines the specific fuel consumption increases by +0.34% per percent cooling air reduction. With a reduction in cooling fraction, the exhaust pressure of the core increases, resulting in a higher thrust (up to 2.3%). It is shown that the optimal take-off bypass ratio for minimum fuel consumption shifts up, for the GTF2050 engine from 16.4 to 17.5. Furthermore, scenario tests and an exergy analysis were performed to find that the impact of different mechanisms; the pressure loss in heat exchanger has minor impact on performance; change in turbine efficiency has small impact; the effect of changed turbine massflow and heat rejection into the bypass are the dominant phenomena. It is concluded that as a method for reducing fuel consumption, cooled cooling air with the bypass as a heat sink is not feasible for conventional architectures even with extreme design parameters such as high OPR and BPR. Heat rejection to the bypass cannot be effectively utilised and no improvement in core efficiency from reduced cooling air can compensate. In the edge case where there is no heat transfer in cruise, there is an observed specific fuel consumption benefit of up to 4%. The achievable benefit will be lower, however, when accounting for installation penalties. It is recommended to focus turbine cooling studies on the impact and feasibility of active cooling massflow control without heat rejection, investigate alternative heat sinks for cooled cooling air (e.g. cryogenic fuel), and only consider bypass cooled cooling air as last resort when up-flowing cooling schemes is not permissible or ineffective.

The demand for commercial aviation is growing at an annual rate of 4%, posing significant environmental challenges. Large-capacity aircraft designed for long ranges are often used on short-to-medium range routes, leading to inefficient fuel consumption and higher emissions. With a future market need for aircraft seating 211 to 300 passengers, there is a clear gap for such a passenger airliner. This report examines the feasibility of the X-300 EcoFlyer, a proposed short-to-medium range aircraft with reduced environmental impact. Designed to carry 300 passengers over 3000 km, the X-300 aims to achieve 25% lower CO2 emissions, 50% lower NOx emissions, and 20% lower noise emissions compared to the Airbus A320neo. The study covers aircraft functions, system design, performance analysis, manufacturing, sustainability, operations, logistics, business viability, and technical risks. The findings confirm the X-300 EcoFlyer's potential to meet future demands with lower environmental impact. Innovations include a noise-shielding fuselage, a water-injected turbofan engine, in-wheel electrical taxing, and an electrical environmental control system. Overall, the X-300 EcoFlyer represents a promising solution to the challenges facing the future of high-capacity air transport.

The demand for commercial aviation is growing at an annual rate of 4%, posing significant environmental challenges. Large-capacity aircraft designed for long ranges are often used on short-to-medium range routes, leading to inefficient fuel consumption and higher emissions. With a future market need for aircraft seating 211 to 300 passengers, there is a clear gap for such a passenger airliner. This report examines the feasibility of the X-300 EcoFlyer, a proposed short-to-medium range aircraft with reduced environmental impact. Designed to carry 300 passengers over 3000 km, the X-300 aims to achieve 25% lower CO2 emissions, 50% lower NOx emissions, and 20% lower noise emissions compared to the Airbus A320neo. The study covers aircraft functions, system design, performance analysis, manufacturing, sustainability, operations, logistics, business viability, and technical risks. The findings confirm the X-300 EcoFlyer's potential to meet future demands with lower environmental impact. Innovations include a noise-shielding fuselage, a water-injected turbofan engine, in-wheel electrical taxing, and an electrical environmental control system. Overall, the X-300 EcoFlyer represents a promising solution to the challenges facing the future of high-capacity air transport.

The aviation industry is shouting out its aim to reach ”net-zero carbon” by 2050. Nevertheless, air traffic is expected to grow up until then, and if fuel consumption is reduced by new technologies and aircraft, other sources of global warming such as N Ox emissions and contrails are less considered. Therefore, the climate impact improvement of new technologies compared to older ones is not straightforward and requires a deep analysis. This work performs such an analysis via three steps: The selection of a new fleet to be compared with the actual fleet (2019), a comparison between the two fleets emissions via an Aviation Emission Inventory code, and a climate impact assessment with the tool AirClim. The new fleet analysed consists of the replacement of 14 old (entry in service before 2002) Airbus and Boeing aircraft with their new versions (entry in service between 2011 & 2018). The results show a reduction of 8.7% of fuel consumed by total aviation just by replacing the 14 old aircraft with the new ones. On the other hand, it leads to an 8.0% N Ox emissions increase. Nevertheless, the climate impact assessment concludes that this N Ox emissions increase lowers the surface temperature change due to aviation. This is explained by the strong influence of N Ox emissions location on its climate impact. Overall, this new fleet leads to a decrease in temperature change due to aviation in 2050 of 5.3 mK (-5.2%). This work gives important conclusions on the priorities that need to be set for the development of ’greener’ aviation technologies.