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Showing 1 to 17 of 17 for “"Finite-rate Chemistry"”.
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Behavior of a Hypersonic Nozzle Using Finite Rate Chemistry
… of the behavior of a hypersonic nozzle with finite rate chemistry. First, equations describing steady one dimensional flow through a nozzle are presented. Solution methodologies for frozen, equilibrium and detailed chemistry flow are then discussed. A hydrogen-air chemical reaction mechanism, …
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A finite volume method for the Navier-Stokes equations with finite rate chemistry
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1985.
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Topics on spatially high-order accurate methods and preconditioning for the Navier-Stokes equations with finite-rate chemistry
… high order spatial accuracy and convergence-rate acceleration through system preconditioning. Concerning high-order accuracy, the computational qualities of various spatial methods for the finite-volume solution of the Euler equations are presented. The two-dimensional essentially …
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Numerical investigation of effects of pressure and chemistry on characteristics of turbulent premixed flames
… also affect the highly nonlinear turbulence-chemistry interactions (TCIs). Previous fundamental studies characterize TCIs at atmospheric pressure, but relevant devices usually operate at higher pressures. This study investigates the effects of elevated pressure and finite-rate chemistry on …
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Propagation of spherically expanding premixed flames
… unconfined scenario. Also, the effect of stretch rate on local density weighted flame displacement speeds is studied, which indicates toward the consistent definition of the flame displacement speed. The numerical results are compared with a non-linear analytical model that treats the flame as a …
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Propagation of premixed flames in confined channels
… to obtain properties like the mass burning rate, pressure and flame location as a function of time, velocity field in the channel and propagation speed. Also the temperature and concentration profiles are obtained which give an insight in to the thickness of the flame region as the flame …
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Modeling ignition and extinction in condensed phase combustion
… analysis valid in the limit of low strain rates (high residence time in the reaction zone), a constant mixture density assumption that simplifies the flow description, diffusion models with equal and unequal molecular weights for the various species, and a full numerical study for finite …
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Thermoacoustic Effects of a Variable Equivalence Ratio in a Single Element Methane Combustor
… axisymmetric domain and modeled in Fluent with finite rate chemistry and a hybrid RANS/LES approach. The acoustic analysis and power spectral densities were done with a Fast Fourier Transform algorithm.</p> <p>The dominant frequencies, found to be between 1463 Hz and 1551 Hz, compare well with …
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Flux-split algorithms for flows with non-equilibrium chemistry and thermodynamics
… velocity, high-temperature flow situations, when finite-rate chemistry and non-equilibrium thermodynamics greatly affect the physics of the problem. Two flux-vector-split algorithms, of the Steger-Warming and of the Van Leer type, and one flux-difference-split algorithm of the Roe type are …
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Computational Fluid Dynamics Methodologies for Simulation of Chemical Oxygen-Iodine Laser Flowfields
… (CFD) code GASP which solves the conservative, finite-volume formulation of the full Navier-Stokes equations coupled to a finite-rate non-equilibrium chemistry model. The GASP code was improved to need the demands of COIL simulation by the addition of a conservative, multicomponent molecular …
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Modelling of Spray Combustion with Doubly Conditional Moment Closure
… approach allows us to consider the effects of finite-rate chemistry and spray evaporation on the flame. Using a parametrisation of the flame structure, based on mixture fraction and reaction progress variable permits us to resolve premixed, non-premixed and intermediate combustion modes. In the …
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High Fidelity Chemistry And Radiation Modeling For Oxy-Combustion Scenarios
… atmosphere, several refined gas-phase chemistry and radiative property models have been formulated for laminar to highly turbulent systems. This thesis examines the accuracies of several chemistry and radiative property models employed in computational fluid dynamic (CFD) simulations of …
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Kinetic algorithms for non-equilibrium gas dynamics
… for flows with nonequilibrium thermodynamics and chemistry. These schemes are derived from the Boltzmann equation with the resulting Euler schemes developed as moments of the discretized Boltzmann scheme with a locally Maxwellian velocity distribution. Application of a directionally-split …
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Large eddy simulations of premixed turbulent flame dynamics : combustion modeling, validation and analysis
… onset and proposing passive and active control strategies are critical to large-scale implementation. For the numerical study of such systems, large eddy simulation (LES) techniques with appropriate combustion models and reaction mechanisms are highly appropriate. These approaches balance the …
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Characterization of carbon ablators for hypersonic thermal protection systems
… tool for ground-to-flight condition matching and finite-rate chemistry modeling. These experiments prompted closer study of oxidation - the primary mass loss mechanism for carbon TPS in air - and the influence of diffusion-reaction competition in porous carbon-fiber ablators. Micron-resolution in …
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Predicting Soot Emissions with Advanced Turbulent Reacting Flow Modelling
… reacting flows are required, not only for accurate predictions related to flame characteristics but also to meet increasingly stringent regulations. Over the last decades, advances in the understanding of key processes controlling soot formation and oxidation have led to the development of …
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Oxygen-Enhanced Combustion: Theory and Applications
… previously discussed was modified to account for finite-rate chemistry and residence time effects, and was correlated with experimental data leading to the determination of the critical local temperature and critical local C/O ratio for soot inception in ethylene flames. The presence of …