Vibrational relaxation and triggering of the non-equilibrium vibrational decomposition of CO${}_2$ in gas discharges

Abstract

Non-equilibrium vibrational dissociation of CO${}_2$ at low translational-rotational temperatures $T$ is investigated computationally for conditions of microwave induced plasmas. Semi-analytic treatment of vibrational relaxation in CO${}_2$ in shock tube and acoustic experiments is summarized. A state-to-state vibrational kinetics model applied for the simulations is benchmarked and adjusted to the relaxation times obtained in gas dynamic experiments. The governing parameter $Q/n_0^2$ has been introduced, where $Q$ is the specific volumetric power coupled in plasma and $n_0$ is the initial number density of CO${}_2$. The modelling results indicate a rapid increase of the rate of the primary dissociation process CO${}_2$ + M $\to$ CO + O + M when $Q/n_0^2$ exceeds some critical value. A simple analytic calculation of ${\left(Q/n_0^2\right)}_{crit}$ is proposed which agrees well with the numerical results. At $T$=300 K the estimated ${\left(Q/n_0^2\right)}_{crit}\eqsim 6\cdot 10^{-40}$~W$\cdot$m${}^3$.

References in corpus (2)

• Performance analysis of a 2.45 GHz microwave plasma torch for CO${}_2$ decomposition in gas swirl configuration
• Heavy-Impact Vibrational Excitation and Dissociation Processes in CO${}_2$

Cited by in corpus (1)

• Validation of non-equilibrium kinetics in CO2-N2 plasmas