Numerical simulation of S-shaped inlet under the intake total pressure distortion

Ying Liu,Congrui Cai,Bateng Wu,Yang Yu,Xiaobo Zhang,Bingkun Yan,J Zhu

doi:10.1051/matecconf/202235501017

Abstract

During the development of the stealth fighter, the S-shaped inlet enters the designer’s vision because it has better stealth than bump inlet and straight inlet. During the use of the S-shaped inlet, due to its structural reasons, secondary flow is likely to occur in the curved section, which directly causes the flow state to be changeable and complicated. Therefore, this paper takes the S-shaped inlet as the research object to analyzes the steady flow field simulation under uniform inlet condition and distortion inlet condition and analyze the flow field of the airflow and the total pressure of each section under the S-shaped inlet by changing the intake distortion conditions with CFX software. The results show that although the S-shaped inlet will occur total pressure distortion under uniform intake. However, when the S-shaped inlet work under certain flight conditions, the level of total pressure distortion will be smaller than the uniform inlet condition, which can improve the air intake performance. Finally, it can be inferred that with use of the S-shaped intake port, the deterioration of distortion may be prevented under certain specific intake conditions.

Highlights

In the development of stealth fighters, in order to pursue a better stealth effect, the Sshaped inlet has entered people's field of vision because it can reduce the RCS
Based on the historical research results, this paper explores the intake performance of the S-shaped inlet by simulating the flow field under the actual distortion conditions such as the angle of attack state and the suction ground vortex state, and comparing the effect of distortion index under the axial uniform intake distortion
This section simulates the air intake distortion state of the S-shaped inlet under the flying condition of the elevation angle when the aircraft is manoeuvring at low speed

Summary

Introduction

In the development of stealth fighters, in order to pursue a better stealth effect, the Sshaped inlet has entered people's field of vision because it can reduce the RCS. The use of S-shaped inlet will affect the intake efficiency of the engine, so international experts and scholars have carried out experiments and analyses on its performance. Lin [12,13] had carried out related research on the S-shaped inlet at high angles of attack and the rectangular variable circular cross-section S-shaped inlet. In order to more comprehensively analyse the air flow status under S-shaped inlet at low speeds and large angles of attack. Based on the historical research results, this paper explores the intake performance of the S-shaped inlet by simulating the flow field under the actual distortion conditions such as the angle of attack state and the suction ground vortex state, and comparing the effect of distortion index under the axial uniform intake distortion

Distortion index

Inlet distortion under uniform intake conditions

Inlet distortion under angle of attack

Inlet distortion under indraft ground vortex

Conclusion