Study on the Flow Characteristics of Nacelle Intake with Fan Compression under Ground Conditions

The quality of the nacelle intake flow not only affects the stability and performance of the engine, but also determines the flow quality. The next-generation civil turbofan engine requires a short intake length and larger lip thickness. However, the thicker lip is more likely to be separated, and the shorter intake will cause the total pressure or distortion disturbance to be transmitted to the fan, which increases the inhalation of ground vortices. Therefore, it is essential to study the influence of special conditions (such as side wind conditions) on the flow characteristics of the intake to improve the engine intake performance quality and operating stability. In this paper, numerical simulation calculations have been carried out to study the performance of the isolated nacelle intake and the intake with the impact of fan compression under ground conditions (such as taxiing and side wind conditions). For the isolated intake, a smaller crosswind velocity will form a stronger ground vortex. With the increase of the crosswind velocity, the ground vortex gets weaker, and the distortion index changes rapidly, of which the rate of change of distortion index with crosswind velocity can reach up to 14.53%. At the same time, the change of the crosswind angle will also have a significant impact on the intake distortion index. When there is a full crosswind, the pressure loss is the largest, and the total pressure recovery coefficient is the lowest. For the fan compressed intake, changing the crosswind velocity and angle will change the changing trend of the performance parameters of intake. The sensitivity of the distortion index and the total pressure recovery coefficient to the change of the crosswind angle is enhanced. The change rate of the distortion index can increase up to 44.4%.