Comparative modeling of N2 molecules dissociation in thermally non-equilibrium conditions

Fluid, gas and plasma mechanics


Pogosbekian M. Y.*, Sergievskaya A. L.**, Kroupnov A. A.***

Institute of Mechanics Lomonosov Moscow State University, 1, Michurinsky prospect, Moscow, 119192, Russia



At strong shock waves in rarefied gases, chemical processes such as dissociation and exchange reactions occur in conditions of thermodynamic non-equilibrium, and the rate coefficients are the functions of both translational—rotational and vibrational temperatures.

The object of the study are chemical reaction models of the of N2 molecules dissociation occurring in thermally non-equilibrium conditions.

The goal of the work consists in comparative study of physico-chemical processes models on the example of dissociation of nitrogen molecules. For comparison, the well-known and frequently used theoretical dissociation models, representing the process in a single-temperature, two-temperature, and level approximation, were chosen. The article presents a detailed description of theoretical models allowing calculate the goal functions of the N2 molecule dissociation models in thermally non-equilibrium conditions, both in the two-temperature and in the level approximations. To perform a valid and reliable comparison, in addition to theoretical models, the results of molecular dynamics of N2 molecules modeling obtained by the classical trajectory method, as well as data from a physical experiment on a shock tube are used.

To simulate molecular dynamics, the computer “MD Trajectory” complex was used. Computational experiments with theoretical models were performed in the environment of the Internet Catalog of physical and chemical processes models.

A new functional, depending on the translational temperature and expression for the empirical parameter of the Marrone-Treanor model was proposed based on the comparison. The modified model application allows describe the results of trajectory calculations in a wide range of translational temperatures from 2000 to 10000°K.


levels of description, dissociation, processes models, velocity constant, non-equilibrium factor, level factor, classical trajectories method, experiment


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