A comprehensive theoretical/numerical model for treating AP/HTPB composite-propellant combustion in a rocket-motor environment is presented. The formulation takes into account the conservation equations in both the gas and condensed phases, and accommodates finiterate chemical kinetics and variable thermophysical properties. The processes in the two phases are coupled at the surface to determin...

A recent numerical study of turbulence-flame interactions in lean premixed hydrogen, where the Lewis number was approximately 0.36, observed that flames at different equivalence ratios presented significantly different behavior despite having the same Karlovitz and Damköhler numbers. This differing behavior is due to the thermodiffusively-unstable nature of low Lewis number flames. In more than...

Modern high speed aerospace propulsion relies on the development of scramjet engines significantly. Design of a supersonic combustor involves the potential problems of proper mixing, flame holding as well as flame stabilization within the very short period. Many techniques were introduced to overcome these problems, of which cavity flame holders has evolved as one of the prominent among them. T...

Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr ≪ 1, and laminar flame speed, SL. We find that i...

The description of chemical kinetics in turbulent reactive flows is an important task to improve combustion models. This paper describes the inclusion of detailed chemical reaction mechanisms into the framework of a turbulent flame simulation. Calculations are based on a finite-volume solution procedure including submodels for turbulent flow, combustion of fuel and radiative heat transfer. The ...

Turbulent multi-phase combustion is encountered in a number of engineering applications, such as internal combustion engines and gas-turbine aircraft engines. Therefore, the ability to perform accurate numerical simulations of these systems is of paramount importance to improve their design and efficiency. However, the underlying physics of spray combustion are extremely complicated. The liquid...

We report a large-eddy simulation (LES)/probability density function (PDF) study of a non-premixed CO/H2 temporally-evolving turbulent planar jet flame, which has previously been studied using direct numerical simulations (DNS) with a skeletal chemical mechanism. The flame exhibits strong turbulence– chemistry interactions resulting in local extinction followed by re-ignition. In this study, th...

Experimental, modeling, and direct-numerical-simulation (DNS) studies have advanced our understanding of turbulence and mixing. The mixing transition, that occurs across a broad spectrum of flows, at outer-scale Reynolds numbers in the vicinity of Re δ ≈ 1 − 2 × 10 4 , or Taylor Reynolds numbers of Re T ≈ 100 − 140, will be discussed. Inflow-/initial-condition effects in high-Re shear layers wi...