一种带前输出轴的直升机进气道性能试验研究

本文针对带有前输出轴直升机进气道结构特点，以实验的方法，着重研究在悬停与前飞状态下的直升机进气道流场特性，测量并分析了沿程静压分布、进气道出口截面流场畸变指数、总压恢复系数等进气道性能参数。结果表明，此类进气道在悬停与前飞状态下进气道内均存在某种程度的气流分离，在悬停状态时总压损失和出口流场畸变都不大，但在前飞状态时由于自由流直接进入进气道外侧，使得出口流场畸变变大，且随着前飞速度的增加出口流场不断恶化。

AN INVESTIGATION OF THE FLOW IN A HELICOPTER INTAKE WITH FRONT OUTPUT SHAFT

An experimental study of the flow in a helicopter intake with front output shaft was conducted in low speed wind tunnel. The flow characters of the intake at hover and forward flight are presented in this paper. The static pressure distributions along duct, distortions of the flow field at the intake outlet section and total pressure recovery coefficient had been measured and analyzed. The results indicate that there is a local flow separation at the downstream of tip highlight near the outside wall and lower wall of the duct for hover and forward flight respectively. The distortion of the flow at outlet section of the intake is relevant to the forward speed of the helicopter and the flow speed at outlet section. During the flow speed at outlet section keeps constant the distortion of the flow deteriorates with the increase of the forward speed because the flows in the intake have not been mixed sufficiently.