High-pressure two-species mixing in turbulent free jets

Abstract

Engine performance and exhaust gas composition in numerous automotive/aerospace propulsion systems depends on the fuel-oxidizer mixing at high pressures. A fundamental understanding of the high-pressure (p) flow dynamics is hence key to improving the engine efficiency. Turbulent round jet direct numerical simulations are performed in this study at a Reynolds number (based on jet diameter and jet-exit velocity) of 5000 to understand binary-species mixing in supercritical conditions. For comparison, single-species flows at atmospheric as well as supercritical pressure are also investigated. The effects of species-concentration gradients on thermal and mass diffusion are significant in a binary-species flow. Moreover, large density (or thermodynamic) fluctuations can occur because of the differences in injected and chamber fluid density/temperature resulting in noticeable Soret effects. The paper discusses preliminary results from an investigation eventually aimed at examining multicomponent species injection and mixing.

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