Multicomponent transport algorithms for partially ionized mixtures

Combustion Theory and Modelling

Matuszewski

Dupoirieux

2011

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We first investigate a detailed high pressure flame model. Our model is based on thermodynamics of irreversible processes, statistical thermodynamics, and the kinetic theory of dense gases. We study thermodynamic properties, chemical production rates, transport fluxes, and establish that entropy production is nonnegative. We next investigate the structure of planar transcritical H 2 -O 2 -N 2 flames and perform a sensitivity analysis with respect to the model. Nonidealities in the equation of state and in the transport fluxes have a dramatic influence on the cold zone of the flame. Nonidealities in the chemical production rates-consistent with thermodynamics and important to insure positivity of entropy production-may also strongly influence flame structures at very high pressures. At sufficiently low temperatures, fresh mixtures of H 2 -O 2 -N 2 flames are found to be thermodynamically unstable in agreement with experimental results. We finally study the influence of various parameters associated with the initial reactants on the structure of transcritical planar H 2 -O 2 -N 2 flames as well as lean and rich extinction limits.

Section: Diffusion Matricesmentioning

confidence: 99%

Detailed modeling of planar transcritical H₂–O₂–N₂flames

Combustion Theory and Modelling

Matuszewski

Dupoirieux

2011

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“…New algorithms have been thus been introduced with more singular versions of the transport linear systems. These algorithms have led to fast convergence rates for all ionization levels and magnetic field intensities [71].…”

Section: Transport Coefficientsmentioning

confidence: 99%

“…We notably address the mathematical structure of the transport linear systems and fast accurate evaluation of the transport coefficients [65,66,67,68,69,70,71]. We also present a typical numerical simulation of a complex chemistry Bunsen laminar flames [5,72,73,74] and discuss the impact of multicomponent transport [75,76,77,78,79,80] as well as possible extensions [81,82,83,84,85,86,87,88].…”

Section: Introductionmentioning

confidence: 99%

Multicomponent flow modeling

2011

Sci. China Math.

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We first present multicomponent flow models derived from the kinetic theory of gases. We then investigate the symmetric hyperbolic-parabolic structure of the resulting system of partial differential equations and discuss the Cauchy problem for smooth solutions. We also address the existence of deflagration waves also termed anchored waves. We further indicate related models which have a similar hyperbolic-parabolic structure, notably the Saint-Venant system with a temperature equation as well as the equations governing chemical equilibrium flows. We next investigate multicomponent ionized and magnetized flow models with anisotropic transport fluxes which have a different mathematical structure. We finally discuss numerical algorithms specifically devoted to complex chemistry flows, in particular the evaluation of multicomponent transport properties, as well as the impact of multicomponent transport.

“…Finally, it is remarkable that the chemical potentials µ i , i ∈ S, are involved with thermodynamics, with the transport fluxes (6.5)(6.6) as well as the chemical production rates (4.3). The determination of flame structures is based on adaptive flame solvers [63], adaptive continuation techniques [52], as well as optimized thermochemistry and transport libraries [64,65,66,67,68]. We present in Figure 3 the structure of a stoichiometric H 2 -air flame with T fr = 100 K and p = 200 atm.…”

Section: Hydrogen-air Transcritical Flamesmentioning

confidence: 99%

Supercritical fluid thermodynamics from equations of state

Physica D: Nonlinear Phenomena

Matuszewski

2012

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Supercritical multicomponent fluid thermodynamics are often built from equations of state. We investigate mathematically such a construction of a Gibbsian thermodynamics compatible at low density with that of ideal gas mixtures starting from a pressure law. We further study the structure of chemical production rates obtained from nonequilibrium statistical thermodynamics. As a typical application, we consider the Soave-Redlich-Kwong cubic equation of state and investigate mathematically the corresponding thermodynamics. This thermodynamics is then used to study the stability of H2-O2-N2 mixtures at high pressure and low temperature as well as to illustrate the rôle of nonidealities in a transcritical H2-O2-N2 flame.