Accession Number : AD1015514

Title :   Nonequilibrium Molecular Energy Coupling and Conversion Mechanisms

Descriptive Note : Technical Report,01 Sep 2012,14 May 2016

Corporate Author : OHIO STATE UNIV COLUMBUS COLUMBUS United States

Personal Author(s) : Adamovich,Igor V ; McCoy,Anne B

Full Text :

Report Date : 28 Aug 2016

Pagination or Media Count : 99

Abstract : The report presents results of development of an accurate, physics-based model of vibrational and rotational energy transfer in three-dimensional collisions of rotating diatomic molecules, applicable over a wide range of collision energies and vibrational / rotational quantum numbers, and results of detailed kinetic modeling studies of state-to-state molecular energy transfer processes, including excitation of vibrational and electronic states by electron impact, collisional quenching of excited electronic states, vibration-vibration (V-V) energy transfer, vibration-rotation-translation (V-R-T) relaxation, internal mode energy thermalization, molecular dissociation (both by electron impact and during quenching of excited electronic state), and plasma chemical reactions. The kinetic modeling prediction are compared with recent time-resolved, spatially resolved measurements of vibrational level populations, gas temperature, and atomic species and radical number densities in the afterglow of a ns pulse discharge generating strong internal energy mode disequilibrium in air and fuel-air mixtures. The present results provide new quantitative insight into kinetics of molecular energy transfer and plasma chemical reactions in air and fuel-air mixtures, at the conditions of strong internal energy mode disequilibrium. Closed-form, physics-based, analytic expressions for state-to-state rotational and vibrational energy transfer transition probabilities lend themselves to straightforward incorporation into state-of-the-art DSMC nonequilibrium flow codes. Understanding kinetics of energy thermalization and chemical reactions in ns pulse discharges considerably improves predictive capability of kinetic models, which has major implications for plasma assisted combustion and high-speed plasma flow control, where these discharges are used increasingly widely.

Descriptors :   chemical kinetics , vibrational relaxation , electron energy , computational modeling

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Operations Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE