Abstract
In this study, numerical simulations were conducted to confirm the possibility of improved mixing performance by using a fluidic oscillator as a fuel injector. Three-dimensional URANS non-reacting simulations were conducted to examine air–fuel mixing in a supersonic flow field of Mach 3.38. The numerical methods were validated through simulations of the oscillating flow generated from the fluidic oscillator. The results show that the mass flow rate and momentum are reduced at the outlet because the total pressure loss increases inside the fluidic oscillator, which means that higher pressure needs to be applied to supply the same mass flow rate. The simulation showed that the flow structure varies over time as the injected flow is swept laterally. With lateral injection, the fuel distribution is long and narrow, and asymmetric vortexes are generated. However, with central injection, the fuel distribution is relatively similar to the case of using a simple injector. Compared to the simple injector, the penetration length, flammable area, and mixing efficiency were improved. However, the total pressure loss in the flow field increases as well. The results showed that the supersonic fluidic oscillator could be fully utilized as a means to enhance the mixing effect, however a method to reduce the total pressure loss is necessary for practical application.
Highlights
A scramjet engine is a next-generation engine that can be operated in the hypersonic regime.Many studies have been conducted since the concept of supersonic combustion was presented byFerri [1], but scramjets have not yet been developed to the stage of practical application due to technical difficulties
The results showed that the unsteady flow field near the injector improves the penetration length and mixing performance
For aCharacteristics reasonable comparison previous studies [25,44], the fluidic oscillator model was scaled down to have the same diameter of 2 mm at the inject exit
Summary
A scramjet engine is a next-generation engine that can be operated in the hypersonic regime. The air from the intake flows at supersonic speed, so the fuel and air have a very short residence time in the combustion chamber To overcome this issue, many studies have been conducted on more efficient and faster air–fuel mixing techniques, which are largely divided into passive and active methods [2]. Numerical simulations were conducted to confirm that air–fuel mixing can be increased when a fluidic oscillator is appliedwere to a supersonic field. Numerical simulations conducted flow to confirm that air–fuel methods mixing can be validated previous study on fuel injection in a supersonic. Theagain fluidicfor oscillator was thenflow applied to a supersonic flow numerical methods were validated the oscillating induced by the fluidic field to inject fuel The numerical results were compared with experimental results and other numerical results obtained using a simple injector [25,44]
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