The flow over a short intake is characterised by a strong interaction with the fan,that can only be captured when the rotor blades are modelled in the numerical simulations.In this paper,we use a coupled methodology to derive indications about relevant geometric variables affecting the high-incidence operation of an ultra-high bypass ratio turbofan intake with a length-to-diameter ratio of 0.35.By reproducing the effect of the fan through a body force model,we carry out a para-metric study of the influence of the contraction ratio and the scarf angle at take-off conditions for a grid of 28 different three-dimensional shapes.The analysis of the selected performance metrics dis-tributions at three angles of attack of 16°,24°,and 28° reveals that a contraction ratio higher than 1.20 is needed to avoid separation at high incidence.While for an attached inlet the best perfor-mance is found with a moderate scarf angle,in presence of a developed separation the distortion level reduces as the scarf decreases up to negative values.We discuss the correspondence between the distortion indexes and the flow field,highlighting the origin of the detachment for the different geometries,according to the operating condition,and analysing the fan operation in the most dis-torted case.Finally,we assess the influence of modelling the rotor in the simulations,showing that its suppression effect on the separation at a given incidence depends on the intake geometric fea-tures.

Andrea MAGRINI;Ernesto BENINI

Dipartimento di Ingegneria Industriale,Universitá degli Studi di Padova,Padova 35131,Italy

中国航空学报（英文版）

[1]Andrea MAGRINI;Ernesto BENINI-.Study of geometric parameters for the design of short intakes with fan modelling)[J].中国航空学报（英文版）,2022(11):18-32

turbofan,scarf,torted

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