Kinetic model for chemical reactions in hypersonic non-equilibrium flows

PAMM ◽  
2005 ◽  
Vol 5 (1) ◽  
pp. 533-534 ◽  
Author(s):  
Florian Zus ◽  
Herbert Olivier
Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 179 ◽  
Author(s):  
Ramon Álvarez-Estrada

We review and improve previous work on non-equilibrium classical and quantum statistical systems, subject to potentials, without ab initio dissipation. We treat classical closed three-dimensional many-particle interacting systems without any “heat bath” ( h b ), evolving through the Liouville equation for the non-equilibrium classical distribution W c , with initial states describing thermal equilibrium at large distances but non-equilibrium at finite distances. We use Boltzmann’s Gaussian classical equilibrium distribution W c , e q , as weight function to generate orthogonal polynomials ( H n ’s) in momenta. The moments of W c , implied by the H n ’s, fulfill a non-equilibrium hierarchy. Under long-term approximations, the lowest moment dominates the evolution towards thermal equilibrium. A non-increasing Liapunov function characterizes the long-term evolution towards equilibrium. Non-equilibrium chemical reactions involving two and three particles in a h b are studied classically and quantum-mechanically (by using Wigner functions W). Difficulties related to the non-positivity of W are bypassed. Equilibrium Wigner functions W e q generate orthogonal polynomials, which yield non-equilibrium moments of W and hierarchies. In regimes typical of chemical reactions (short thermal wavelength and long times), non-equilibrium hierarchies yield approximate Smoluchowski-like equations displaying dissipation and quantum effects. The study of three-particle chemical reactions is new.


2016 ◽  
Vol 18 (30) ◽  
pp. 20135-20143 ◽  
Author(s):  
Tobias Göppel ◽  
Vladimir V. Palyulin ◽  
Ulrich Gerland

A model system illustrates how the coupling efficiency of a physical non-equilibrium to a chemical reaction is affected by the relative timescales of the respective kinetics.


2009 ◽  
Vol 23 (03) ◽  
pp. 297-300
Author(s):  
JIANGFENG WANG ◽  
YIZHAO WU ◽  
KEMING CHENG

Two dimensional hypersonic magnetohydrodynamics(MHD) flows with the chemical non-equilibrium effects are numerically simulated using upwind splitting scheme based on unstructured meshes. The governing equations are 2D MHD equations with the chemical components, where 5 species and 17 chemical reactions are considered. The AUSM scheme is implemented in the spatial discretization for the MHD equations, and an explicit 5-stage Runge-Kutta scheme is used for time integration. A loosely coupled approach is used to communicate between the MHD equations and the chemical reaction model. The computational model is a 2D blunt body, around which a dipole magnetic field is located. With hypersonic incoming flows, four different cases are numerically simulated to analyze the effects caused by the magnetic field and/or non-equilibrium chemical reactions. Numerical results are obtained and compared well with available data.


1979 ◽  
Vol 9 (3) ◽  
pp. 321-327 ◽  
Author(s):  
R. S. Schrebler Guzm�n ◽  
J. R. Vilche ◽  
A. J. Arv�a

1973 ◽  
Vol 10 (3) ◽  
pp. 425-431
Author(s):  
Ta-Ming Fang

A previously developed set of kinetic model equations for a chemically-reacting gas is modified. By examining closely the H theorem, a new set of constraints is obtained. These conditions are then used to determine the inelastic collision parameters proposed in the model. The kinetic equations so obtained are able to produce exactly the same rate equations as prescribed by the actual chemical reactions.


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