The mixing loss in S-shaped duct causes the contradiction between the total pressure recovery and circumferential distortion, which confuses the design process for boundary layer ingestion (BLI) inlet. This article is aiming to present a detailed understanding of the effect of two kinds of loss resources (mixing loss and frictional loss) on the performance for various BLI inlet geometries. To achieve the above objective, a design method including three control parameters is established. With this method, a systematic investigation of control parameters on the performance of BLI inlet is carried out, which leads to the contour map for the performance of BLI inlet. Based on the map, the flow physics of BLI inlet with two kinds of losses is then analyzed. Finally, an empirical design principle is provided. The results show that the appropriate design for BLI inlet has the potential to increase the total pressure recovery or reduce the circumferential distortion.

S形管道中的混合损失导致总压力恢复与周向变形之间的矛盾，这使边界层吸入口（BLI）入口的设计过程变得混乱。本文旨在详细介绍两种损耗资源（混合损耗和摩擦损耗）对各种BLI进气口几何形状性能的影响。为了实现上述目的，建立了包括三个控制参数的设计方法。通过这种方法，对BLI进气口性能的控制参数进行了系统研究，从而得出了BLI进气口性能的等高线图。根据该图，分析了两种损失的BLI入口的流动物理特性。最后，提供了经验设计原则。