关键词: 直升机, 近地面飞行, 扬沙抑制, 旋翼, 布局参数

Abstract:

To address the practical problems of complex sand and dust take-off and landing in helicopter field training operations， a comprehensive modeling and analysis method for near-earth sand blowing of helicopters is established by finely constructing the rotor near-earth interference flow field and incorporating into the sand Discrete Element Method （DEM） model and Hertz-Mindlin sand collision force model. Moreover， UH-60A standard rotor is used to verify the simulation reliability of coupled flow field and sand blowing characteristics. On this basis， the parameters of rotor arrangement research based on helicopter near-earth sand suppression is carried out. By comparing the vortex intensity of blade tip and ground jet velocity in different schemes and analyzing the corresponding flow field-sand blowing characteristics， the influence of blade lower diagonal angle and advanced three-dimensional blade tip （BERP-like shape） on sand suppression is evaluated. The results show that， reducing the blade lower diagonal angle increases the tip vortex intensity and ground jet velocity， thereby increasing the outward expansion radius of sand track line and improving the visibility of dust environment.Compared with parabolic blade tip， the strong tip vortex of BERP-like blade can also increase the intensity and velocity of ground jet after impacting with the ground， offering better suppression effect on the rise of sand and dust on the ground and improving the pilot’s safe flight vision range.

Key words: helicopter, near-earth flight, sand suppression, rotor, parameters of rotor arrangement