Vorticity ( s − 1 ) and its source term ( s − 2 ) Mass production of species α, kg / ( m 3 Viscous and Reynolds stress tensor, kg / ( m Ĭhemical time scales of chemistry, subgrid scale, and micromixing, s Kinematic, turbulent, and effective viscosity, m 2 / sįorward and reverse stoichiometric coefficient of the k th reaction Small quantity to avoid zero division, usually 1 × 10 − 30 Velocity vector, i th component and fluctuation, m/s Squared ratio of model length scale to wall distance Gas constant ( J / ) and universal gas constant ( ≈ 8.314 J / ) Numbers of species, reactions, and mesh cellįlow rate of air crossflow or fuel jet, g / s The forward and reverse rate constants of the β th-elementary reaction Molar concentration of species α, mol / m 3Ībsolute and total absolute enthalpy, J/kg Molar concentration of species i, mol / m 3 The turbulence-chemistry interaction is then analyzed by the aid of numerous quantitative indices, such as Damköhler number, PaSR coefficient, and scalar dissipation rate, as well as their correlation statistics to identify the main combustion modes in the scramjet combustor. The vorticity and its evolution are analyzed through the five source terms for the two cases. The supersonic flow, mixing, and combustion characteristics under the two fuel/air ratios are quantitatively compared based on the efficiency indices, Takeno Flame Index, and the correlation statistics between heat release rate and mixture fraction. The time-averaged static pressure and wall heat flux profiles are well predicted for both fuel-lean and stoichiometric cases. A one-dimensional solid-gas-liquid coupling method is developed to simulate the active cooling effect. A skeletal mechanism consisting of only 28 species and 92 reactions is reduced for the kerosene combustion modeling. A reformulated partially stirred reactor (PaSR) is proposed to adapt it for high mesh resolution. Improved delayed detached Eddy simulation (IDDES) modeling based on a developed skeletal combustion mechanism of kerosene/air is conducted for a full-scale actively cooled scramjet combustor under two different global equivalence ratios.
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