S弯进气道中自动定位叶片对气流流动影响的研究

对Ｓ弯扩压管道内安置自动定位叶片后的气流流动特性进行了实验研究。结果表明，位于模型进气口处的可转动叶片在气流作用下能有两个自动稳定的位置。如果忽略可转动叶片转动轴的摩擦力矩，当叶片处在这两个自动稳定位置时，气流对叶片的合作用力矩为零。研究结果还进一步表明，自动定位叶片对Ｓ弯进气道出口压力场与速度场起着重要作用。本研究为以后如何采取叶片技术抑制Ｓ弯进气道出口的旋流流动，以及模拟旋流流动提供了重要技术基础。

EFFECTS OF AUTOMATICALLY POSITIONING BLADE ON FLOW CHARACTERISTICS IN AN S-SHAPED AIR INLET

An automatically positioning blade with a NACA 0012-series profile was placed upstream near the throat of an S-shaped diffuser and experimented to investigate the characteristics of the flow behind it.The results show that two angular positions have been found where the blade experiences no resultant aerodynamic moment,i.e. 15° and -12°.Moreover,the swirls at the duct exit have different senses of rotation when the blade is held at these two angles.The study lays the foundation for suppression of the duct swirl and its simulation.