California Institute of Technology Pasadena United States
The research studied the dispersion and mixing in turbulent flows with applications to high-speed, air-breathing propulsion. Experiments investigating molecular mixing in high-speed internal flows demonstrated that fuel injection through a perforated inclined ramp can lead to considerable mixing enhancement compared to free-shear layers, with small attendant total-pressure losses. Numerical large-eddy simulations LES with subgrid-scale SGS modeling successfully captured the large-scale features of this flow except for near-wall separation, the observed recirculating flow, chemical product formation under lean- and rich-reactant conditions, and molecular mixing for the first time. A modification will enable investigations of inclined-jet injection, with and without a downstream shear layer. As part of the research on hydrocarbon flames, a new facility was designed and fabricated . Preliminary experiments demonstrated stable flame operation at pressures in excess of 5 atm. Separate investigations of scalar dispersion and mixing in grid turbulence elucidated the importance and role of injection details through their influence on the characteristics of the resulting flow.