Alterations of Cowl Lip for the Improvement of Supersonic-Intake Performance

Abstract

This paper discusses the performance enhancement of supersonic air intake model through the implementation of blunted leading edge to the cowl lip section of the model. A supersonic air intake model with sharp cowl leading edge is initially considered to numerically investigate its performance. Mach 3, supersonic intake flow through the base model has been simulated using commercial CFD package Ansys Fluent-15. Comparison of numerical predictions and experimental measurements is presented to demonstrate the correctness and accuracy of numerical frame work followed in the present study. Higher order spatial accuracy of the solver along with suitably refined mesh helped in accurate capturing of the flow field. Modification to the cowl lip is proposed as an effective method to improve the performance of the supersonic air intake. Two different blunted cowl leading edge geometries were investigated to identify the possible enhancement in performance parameters. Improvement in mass capture and combustion stability attained through the use of forward shifted blunt cowl leading edge is presented. It is also revealed through the present study that the blunt cowl leading edge can reduce the intensity of shock wave boundary layer interaction occurring at the isolator entry section. Deviation in total pressure recovery and flow distortion observed with different supersonic air intake models are also discussed with reasons for the same. This study demonstrates the scope of overall improvement in scramjet engine performance through the use of suitably positioned blunt cowl leading edge.

Control of a Supersonic Inlet in Off-Design Conditions with Plasma Actuators and Bleed

“…In Figure 5 the wall pressure distribution normalized with respect to the far field total pressure is reported. The plot shows a comparison between the experimental results from [58], the present numerical results and the numerical results obtained with the SST k − ω [30] and k − [31] models by [59]. All the numerical simulations tend to underestimate the pressure on the second ramp but they are very close to each other.…”

“…grid, present work SA, medium grid, present work SA, fine grid, present work k-[59] k-[59] Exp [58]. Comparison of the wall pressure distribution at M ∞ = 3 with experimental and numerical results from literature.…”

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

“…These aspects can significantly impact the overall intake performance, and flow behavior can vary depending on the intake's characteristics. Several studies have explored design optimization [45][46][47], while others have investigated how various intake configurations perform at off-design conditions or how different flow control methods can be used to prevent flow unsteadiness. These studies share a common goal: to widen the operational range and increase the efficiency of high-speed intakes.…”

“…With a small cowl deflection, the shock can be weakened, and the flow separation suppressed, possibly improving intake performance [52]. The design optimization of the cowl lip is more commonly investigated in steady flows, and any alterations can notably influence cowl drag, mass-capture, heat loads, and total pressure recovery [9,46,47,[53][54][55][56]. While Fisher [33] discussed various oscillation amplitudes with varying cowl lip positions during intake buzz, Shi et al [57] described the buzz evolution process influenced by the translation of the cowl.…”

Experimental Study of the Unstart/Restart Process of a Two-Dimensional Supersonic Inlet Induced by Backpressure

“…The inlets must operate in the started mode for proper function. The inlets in an unstarted mode typically capture less air flow and have low air compression efficiency (Wagner et al 2012a;Li et al 2013;John and Senthilkumar 2018), which could be dangerous for the scramjet or even the whole vehicle (Voland et al 2013;Shimura et al 1998;Tan et al 2009;Poggie et al 2015). Inlet unstart issue has attracted much attention by researchers over recent decades.…”