Design and analysis of a supersonic axisymmetric inlet based on controllable bleed slots

High-speed air intakes often exhibit intricate flow patterns, with a specific type of flow instability known as `buzz’, characterized by unsteady shock oscillations at the inlet. This paper presents a comprehensive review of prior research, focused on unraveling the mechanisms that trigger buzz and its implications for engine stability and performance. The literature survey delves into studies concerning complex-shaped diffusers and isolators, offering a thorough examination of flow aerodynamics in unstable environments. Furthermore, this paper provides an overview of contemporary techniques for mitigating flow instability through both active and passive flow control methods. These techniques encompass boundary layer bleeding, the application of vortex generators, and strategies involving mass injection and energy deposition. The study concludes by discussing future prospects in the domain of engine-intake aerodynamic compatibility. This work serves as a valuable resource for researchers and engineers striving to address and understand the complexities of high-speed air induction systems.

Section: Boundary Layer Bleedmentioning

confidence: 99%

Aerodynamic Instabilities in High-Speed Air Intakes and Their Role in Propulsion System Integration

Philippou,

Zachos,

MacManus

2024

“…Cheng et al [25] proposed a variable geometry inlet concept combined with local sub-flow circulation which can improve the flow capture capability of the inlet at off-design points and keep the total pressure recovery coefficient unchanged. Yuan et al [26] proposed a three-dimensional aerodynamic design scheme of the inlet operating at Ma i = 1.5-4.0 and control laws of the bleed slots are gained. Cai et al [27] proposed an axisymmetric adjustable inlet that can meet both flow distribution and compression requirements of two channels in a wide working range for the precooled combined-cycle engine.…”

Section: Introductionmentioning

confidence: 99%

Flow Coefficient and Starting Performance Prediction of Variable Geometry Curved Axisymmetric Inlet

Sun

et al. 2023

With the development of combined cycle engines, it is urgent to estimate more quickly and accurately the flow capture capacity and starting performance of variable geometry inlets over a wide Mach number range. Based on the flow field and parameter fitting, two prediction methods for the curved axisymmetric inlet with lip translation scheme have been proposed. The method based on the flow field of the reference inlet is more efficient than the parameters-based prediction method, as it can accurately predict the lip translation distance and the corresponding flow coefficient over the entire working range of the inlet without additional numerical calculations. Moreover, the starting Mach number is accurately predicted by the fitting method based on the throat Mach number of the reference inlet, with a relative error of only 0.95% compared to the numerical simulation. The flow coefficient-based method is simple and accurate for predicting lip translation distances with a known starting Mach number, with a relative error of only 1.65% compared to numerical simulations. The prediction approaches can overcome the drawbacks of the standard iterative algorithms and significantly enhance computational accuracy and efficiency.

“…Therefore, the optimal configuration of the compression shock waves is a key issue in the inlet design. Generally, the inlet types of scramjets include the axisymmetric inlet [7][8][9][10][11], two-dimensional inlet, sidewall compression inlet [12], and inward-turning inlet [13][14][15] in which the two-dimensional inlet has been studied substantially [2,3,[16][17][18] because of the advantages of its simple structure, high uniformity of the exit flow field, its ease of integration, and its variable structure design. In addition, the two-dimensional inlet has a representative shock wave configuration, and relevant characteristics could be a good reference for the design of other types of inlets.…”

Section: Introductionmentioning

confidence: 99%

Lagrange Optimization of Shock Waves for Two-Dimensional Hypersonic Inlet with Geometric Constraints

Yue

et al. 2022

The present paper focuses on the Lagrange optimization of shock waves for a two-dimensional hypersonic inlet by limiting the cowl internal angle and inlet length. The results indicate the significant influences of geometric constraints on the configuration of shock waves and performances of an inlet. Specifically, the cowl internal angle mainly affects the internal compression section; the inlet length affects both the internal and external compression sections where the intensity of internal and external compression shock waves shows a deviation of equal. In addition, the performances of optimized inlets at off-design points are further numerically simulated. A prominent discovery is that a longer inlet favors a higher total pressure recovery at the positive AOA; conversely, a shorter inlet can increase the total pressure recovery at the negative AOA.