Engine cycle adaptation method for aircraft on-board systems evaluation considering system-engine interaction

In the assessment of different aircraft on-board systems (OBS) using mission-level metrics like fuel burn, typically the same engine performance model is employed. One example is the comparison of conventional versus bleedless architectures with respect to their impact on mission block fuel. However, especially with the application of ultra-high bypass ratio (UHBR) turbofans, the cycle performance of such engines increasingly varies depending on the power offtakes (POT) requirements of the considered OBS architecture. This paper proposes a method for adapting the thermodynamic engine cycle to accommodate OBS POT requirements based on a given reference cycle. The method iteratively adjusts relevant engine design parameters by employing physical and semi-empirical correlations. The gas turbine simulation software NPSS is embedded into this process, ultimately posing the adapted cycle design point based on the input design parameters. The presented method is applied in the scope of an OBS architecture trade study for a modern mid-range concept aircraft. The results show a -0.7% reduction in block fuel mass for a bleedless OBS architecture with an adapted bleedless engine compared to the same bleedless architecture in combination with a conventional reference engine designed for bleed offtakes. This highlights the importance of integrated OBS architecture studies, for which the engine’s cycle design point and the employed engine performance model is adapted to the POT requirements for more accurate evaluation results.

DDC Class

620.1: Engineering Mechanics and Materials Science

Options

Engine cycle adaptation method for aircraft on-board systems evaluation considering system-engine interaction