An advanced turboprop inlet with a bypass duct plays a crucial role in preventing foreign object damage and ensuring a high-quality airflow to the engine. However, it also introduces an increased flow complexity and design challenge due to the interaction between the propeller and the bifurcated ducts. To address these issues, a combined experimental and computational fluid dynamics (CFD) study was conducted on the aerodynamic performance and flowfield characteristics of a turboprop inlet equipped with a bypass duct considering the propeller interference. A ground suction test bench was utilized for generating the working conditions and the performance was measured by using total pressure rakes and pressure scanners. It is found that the rotational propeller on the one hand does work on and thus increases the total pressure recovery of the inlet, however, on the other hand causes a turning effect on the inlet flowfield structure along the direction of rotation and increases total pressure and swirling flow distortions in the engine duct. Besides, the engine duct and the bypass duct interact with each other. The combined influence of suction effect and the profile induction of the inlet leads to the majority of the shed vortices being drawn into the engine duct. Lastly, the presence of deflectors installed in the engine duct is found to effectively mitigate the secondary flow, thereby reducing the swirl distortion within the engine duct. This study may provide a significant reference to the design and optimization of advanced turboprop inlets with bypass ducts.

中文翻译：

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带螺旋桨的分叉涡轮螺旋桨发动机进气口在地面吸力条件下的气流动力学研究


带有旁通管道的先进涡轮螺旋桨飞机进气口在防止异物损坏和确保发动机的高质量气流方面起着至关重要的作用。然而，由于螺旋桨和分叉管道之间的相互作用，它也带来了增加的流动复杂性和设计挑战。为了解决这些问题，考虑到螺旋桨干扰，对配备旁通管道的涡轮螺旋桨飞机进气口的空气动力学性能和流场特性进行了实验和计算流体动力学 （CFD） 相结合的研究。使用地吸测试台生成工作条件，并使用全压耙和压力扫描仪测量性能。研究发现，旋转螺旋桨一方面做功，从而增加入口的总压力恢复，但另一方面，沿旋转方向对入口流场结构造成转弯效应，增加发动机管道中的总压力和涡流变形。此外，发动机管道和旁通管道相互影响。吸入效应和进气口的轮廓感应的综合影响导致大部分梭形涡流被吸入发动机管道。最后，发现安装在发动机管道中的导流板可以有效减轻二次流，从而减少发动机管道内的漩涡变形。本研究可为带旁路管道的先进涡轮螺旋桨飞机进气口的设计和优化提供重要参考。