26 September 2014
An important part of the ENOVAL project is the evaluation and assessment of the obtained results. Benefits in engine fuel consumption often come at the price of increased weight or drag so that the overall benefit is reduced. For example, increasing the bypass ratio may require the introduction of a gearbox to drive the fan. Consequently, an increase of the thrust specific weight and, due to larger nacelle dimensions, higher engine and installation drag levels are expected. At overall aircraft level, these effects will at some point nullify the reduction of specific fuel consumption. Therefore, it is important to assess engine technologies in terms of fuel consumption installed on the aircraft to obtain the overall benefits and to find the best compromise.
The ENOVAL project studies three rather different engine thrust classes (also called “platforms”) with static thrust ranging from 100 kN to 450 kN. To allow for an evaluation of these platforms, project partner DLR is in charge of developing suitable aircraft and associated flight missions for each engine. These aircraft are then used to derive global sensitivities with respect to engine design parameters, for example the impact of a variation of engine bypass ratio on mission fuel consumption.
In order to allow for a comparison with the current state of technology a reference aircraft has to be designed for each platform and at the same time future target aircraft have to be considered. These target aircraft take into account possible improvements in aircraft technology within the next 10 years. Besides the new engine technologies we assume that the overall aircraft performance will also be affected by improvements in the areas of structures and aerodynamics.
Two different sets of target aircraft are considered. One group of target aircraft uses the same mission requirements in payload and range as the reference aircraft. However, due to the improvements in engine and airframe technology, these future aircraft become more lightweight which also results in smaller wings and lower thrust requirements.
Another set of target aircraft assumes that future air traffic demand will grow more rapidly than the number of take-off and landing slots in the airports. To cope with this scenario they will need to have an increased passenger capacity. Weight and thrust of these aircraft will be at the same level as the reference aircraft.
The derived results are made available to the engine designers so that they can develop engines with maximum efficiency when mounted on possible future aircraft. The aircraft platform results also serve as a means to study the impact of uncertainties concerning our view of the future. In addition, updated engine characteristics are fed back to adapt the aircraft designs to the progress and development during the course of the project.
To contact the Project Coordinator or technical engineers at DLR or RRD (SP1 Lead), please see here.