大攻角下矩形变圆形截面的S形进气道的内流特性

FLOW CHARACTERISTICS IN AN S-SHAPEDRECTANGULAR-ROUND DIFFUSERAT HIGH INCIDENCE

本文给出了0～85°,特别是30～85°攻角下横截面形状由矩形过渡到圆形的S形进气扩压管道在自由射流吹风条件下抽气实验的结果。研究结果表明,随着进气攻角α增大,出口处总压损失系数η_σ,旋流系数SC_(60)增大,流量φ则不断减小;总压畸变指数DC_(60)的变化比较复杂,在0～60°攻角范围内,随攻角的增大而增加,在70°左右畸变指数值反而下降,然后在大攻角条件下畸变指数再度增加。因此在亚音速大攻角下考虑进气道与发动机相容性问题时,只考虑压力畸变是不够的,必须考虑影响发动机工作的旋流因索。本实验研究为高机动飞机进气道之设计及其性能之改进提供了参考依据。

The paper presents the experimental result of flow in a S-shaped rectangular-round diffuser in the incidence range 0°-85°. The diffuser, connected with a pumping set for sucking air through the duct, was tested in the working section of a blowdown tunnel. The study shows that, with increasing incidence, the average total pressure coefficient η。 and swirl coefficient SC60 increase and air flow coefficient φ decreases continuously, but the total pressure distortion Coefficient DC60 goes up from 0° to 60° incidence and comes down around 70°, then rises again at very high incidence. Therefore, in considering intake/engine compatibility at high incidence, not only DC6, but also SC6 has to be paid more attention. The result provides some worth data for the design and improvement of air intake of highly-maneuverable aircraft.