S wirl injectors are widely used to achieve efficient mixing and combustion in propulsion and power-generation systems, including airbreathing engines and liquid rockets. Variation of the kerosene annulus width has a negligible effect on the dominant frequency of the pressure fluctuation, but it changes the amplitude of fluctuation. The resultant flame becomes relatively unstable if the flame thickness is larger than the liquid-oxygen post thickness. Increasing the annulus width, however, imposes a wake region in a broader zone. A wider annulus induces a larger spreading angle of the liquid-oxygen stream, which intercepts the kerosene stream in a more efficient way. The width of the kerosene annulus is found to significantly affect the injector behavior. The flame is found to be stabilized by two counter-rotating vortices in the wake region of the liquid-oxygen post, which is covered by the kerosene-rich mixture. Emphasis is placed on the near-field flow and flame development downstream of the inner swirler. The turbulence/chemistry interaction is treated using a laminar flamelet library approach. The basis of the study is a large-eddy simulation technique combined with a unified treatment of real-fluid thermodynamics.
The mixing and combustion characteristics of liquid-oxygen/kerosene bi-swirl injectors are investigated under the supercritical conditions typical of contemporary rocket engines.
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