The Implication of Injection Locations in an Axisymmetric Cavity-Based Scramjet Combustor

Naresh Relangi,Suppandipillai Jeyakumar,Antonella Ingenito

doi:10.3390/en14092626

Naresh Relangi, Suppandipillai Jeyakumar + Show 1 more

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https://doi.org/10.3390/en14092626

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Abstract

This paper presents the effect of cavity-based injection in an axisymmetric supersonic combustor using numerical investigation. An axisymmetric cavity-based angled and transverse injections in a circular scramjet combustor are studied. A three-dimensional Reynolds-averaged Navier–Stokes (RANS) equation along with the k-ω shear-stress transport (SST) turbulence model and species transport equations are considered for the reacting flow studies. The numerical results of the non-reacting flow studies are validated with the available experimental data and are in good agreement with it. The performance of the injection system is analyzed based on the parameters like wall pressures, combustion efficiency, and total pressure loss of the scramjet combustor. The transverse injection upstream of the cavity and at the bottom wall of the cavity in a supersonic flow field creates a strong shock train in the cavity region that enhances complete combustion of hydrogen-air in the cavity region compared to the cavity fore wall injection schemes. Eventually, the shock train in the flow field enhances the total pressure loss across the combustor. However, a marginal variation in the total pressure loss is observed between the injection schemes.

Highlights

IntroductionThe issues employing supersonic combustion are still unsolved: fuel and oxidizer must mix, ignite, and burn in a very short time, i.e., in a reasonable length avoiding strong shocks within the engine [4]
Supersonic air-breathing engines are the future of high-speed transportation vehicles.Recent studies have witnessed significant progress in the research on scramjets since it is the most suitable and promising engine for the air-breathing hypersonic propulsion [1,2]: the greater specific impulse makes the scramjet appealing for civil and military applications [3].the issues employing supersonic combustion are still unsolved: fuel and oxidizer must mix, ignite, and burn in a very short time, i.e., in a reasonable length avoiding strong shocks within the engine [4]
This paper investigates the effect of different injection strategies in an axisymmetric cavity-based circular scramjet combustor in a reacting flow field

Summary

Introduction

The issues employing supersonic combustion are still unsolved: fuel and oxidizer must mix, ignite, and burn in a very short time, i.e., in a reasonable length avoiding strong shocks within the engine [4]. An effective fuel/air mixing and combustion are hard to achieve in scramjets since the residence time is of the order of milliseconds. To design an efficient fuel injector, mixing, combustion, as well as total pressure losses, must be investigated: there is always a trade-off between the penetration of fuel jet and losses in stagnation pressure since high injection angles lead to strong bow shock which enhances vorticity and mixing inside the flow and strongly affects the total pressure los, Deep understanding is, necessary to answer these key issues

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