Influence of Propeller Slipstream on the Flow Field of S-Shaped Intake

Shuili Ren,Peiqing Liu,Adel Ghenaiet

doi:10.1155/2021/6220378

Shuili Ren, Peiqing Liu + Show 1 more

Open Access

https://doi.org/10.1155/2021/6220378

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Abstract

For turboprop engine, the S-shaped intake affects the engine performance and the propeller is not far in front of the inlet of the S-shaped intake, so the slipstream inevitably affects the flow field in the S-shaped intake and the engine performance. Here, an S-shaped intake with/without propeller is studied by solving Reynolds-averaged Navier-Stokes equation employed SST k-ω turbulence model. The results are presented as time-averaged results and transient results. By comparing the flow field in S-shaped intake with/without propeller, the transient results show that total pressure recovery coefficient and distortion coefficient on the AIP section vary periodically with time. The time-averaged results show that the influence of propeller slipstream on the performance of S-shaped intake is mainly circumferential interference and streamwise interference. Circumferential interference mainly affects the secondary flow in the S-shaped intake and then affects the airflow uniformity; the streamwise interference mainly affects the streamwise flow separation in the S-shaped intake and then affects the total pressure recovery. The total pressure recovery coefficient on the AIP section for the S-shaped intake with propeller is 1%-2.5% higher than that for S-shaped intake without propeller, and the total pressure distortion coefficient on the AIP section for the S-shaped intake with propeller is 1%-12% higher than that for the S-shaped intake without propeller. However, compared with the free stream flow velocity ( Ma = 0.527 ), the influence of the propeller slipstream belongs to the category of small disturbance, which is acceptable for engineering applications.

Highlights

The S-shaped intake has several advantages: (1) its structure is compact [1]; (2) it can decrease the propulsion system resistance [2]; (3) it can decrease the radar sweeping area and improve the aircraft stealth performance [3,4,5]
The geometric characteristic of S-shaped intake is that the centerline has curvature, and the cross section increases in main flow direction [7, 9, 10]
The centerline curvature leads to a pair of counter-rotating vortices, and increase cross section causes streamwise flow separation [11, 12]

Summary

Introduction

The S-shaped intake has several advantages: (1) its structure is compact [1]; (2) it can decrease the propulsion system resistance [2]; (3) it can decrease the radar sweeping area and improve the aircraft stealth performance [3,4,5]. The ideal S-shaped intake can effectively decrease the airflow velocity, increase the airflow static pressure, and provide uniform airflow for engine compressor [7]. The geometric characteristic of S-shaped intake is that the centerline has curvature, and the cross section increases in main flow direction [7, 9, 10]. The centerline curvature leads to a pair of counter-rotating vortices, and increase cross section causes streamwise flow separation [11, 12]. The complex flow phenomena increases the airflow total pressure loss and distortion on the Aerodynamic Interface Plane (AIP), which drops the engine performance, and leads to diversified troubles [7]

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Results

Conclusion