Numerical study on the influence of inlet distortion on integrated nacelle fans based on coupling crosswind and angle of attack

Crosswind and angle of attack are critical factors that influence the safe operation of civil aviation engines, which are also essential criteria in the certification of civil engine airworthiness. Conducting research on the effects and mechanisms of angle of attack and crosswind on the integrated characteristics and flow field of nacelle and fan holds significant engineering value. In this study, a high-bypass-ratio turbofan engine serves as the research subject, and the influence of crosswind and angle of attack coupling on the nacelle intake and fan components is analyzed using numerical simulations. The numerical research findings indicate that both individual angle of attack and crosswind, as well as their combination, lead to a specific range of total pressure distortion in the inlet. At an angle of attack of 25°, the extent and degree of circumferential total pressure distortion formed on the aerodynamic interface exhibit minor variations under different crosswind inflow conditions. Under two operating conditions involving left crosswind and right crosswind, both characterized by an angle of attack of 25° and a wind speed of 20 m/s, the combined effects of crosswind and angle of attack on the fan and outlet guide vane (OGV) components are mainly concentrated at the blade tip. These influencing factors collectively lead to total pressure distortion in the inlet flow field, resulting in the interaction between tip leakage flow and passage shock waves. At the same angle of attack, there are differences in the impact of total pressure distortion caused by crosswinds in two directions on the fan. Under the same operating conditions, the total pressure distortion induced by the right crosswind has a greater impact on OGV.