Civil turbofan propulsion aerodynamics: Thrust-drag accounting and impact of engine installation position

Impact of installation on a civil large turbofan exhaust system at idle descent conditions

“…The aerodynamic analysis for this study utilises the numerical framework developed for the design and analysis of separate-jet high and very high bypass ratio turbofan engines [10,42,12,43,44,26]. In particular, the current study follows the methodology reported by Goulos et al [26] for the design, meshing, CFD analysis, and performance evaluation of aero-engines [10,45,46].…”

“…The aerodynamic analysis for this study utilises the numerical framework developed for the design and analysis of separate-jet high and very high bypass ratio turbofan engines [10,42,12,43,44,26]. In particular, the current study follows the methodology reported by Goulos et al [26] for the design, meshing, CFD analysis, and performance evaluation of aero-engines [10,45,46]. Intuitive Class-Shape Transformation functions (iCSTs) were used for the design of the aerolines for the nozzles, pylon, intake, exhaust and the nacelle [47], in a similar manner as described in Goulos et al [10,48,26].…”

“…This study investigates the impact of installation on the bypass and core nozzle discharge coefficient at idle descent conditions for a HBR engine. The threedimensional (3D) computational ŕuid dynamics (CFD) approach and performance accounting framework developed by Goulos et al [26] is used to assess the aerodynamic effects at three levels of aero-engine integration: an isolated aero-engine with and without a pylon, and an under-wing podded aero-engine mounted on an airframe, which is representative of a typical twin-engine wide-body civil transport airliner. These levels of integration are considered to estimate the impact of the constituent installation effects related to incidence, nozzle pressure ratios, pylon, and airframe-wing interactions.…”

“…For instance, the amount of lift loss by the inclusion of the nacelle and pylon on to an airframe was estimated to be around 10% for an under-wing podded engine [25]. The installation position, and in particular, the overlap of the wing and the nacelle inŕuences the pressure őeld on the nacelle after-body and the exhaust system [13,26], and this inŕuences the discharge coefficient of the exhaust nozzles for both high bypass ratio (HBR) and very high bypass ratio (VHBR) engines. Thus, the wing-pylon-nacelle geometry design optimisation is required to minimise the interference drag between these parts [21,27,28,29,30,31,32].…”

“…While previous studies investigated the impact of aero-engine installation at mid-cruise conditions [13,21,22,23,26,38], there is a dearth of literature on the impact of installation on the engine performance metrics during the descent phase.…”