Internal energy relaxation in nitrogen plasmas

This work discusses the chemical kinetics of nitrogen molecules relaxing in a heat bath at constant temperature in a background gas composed of electrons and nitrogen atoms. The QCT (Quasi-Classical Trajectory) model recently developed at NASA Ames Research Center is used to study energy transfers and population distribution of nitrogen molecules due to collisions with atoms. An ab-initio model developed at the University College London (UCL) is used to study electron impact excitation. Initially, the chemical reactor is filled with cold gas which is suddenly heated up by several thousands of degrees Kelvin to reproduce strong non-equilibrium conditions. The large differences between translational and internal energy in the gas mixture promote energy transfers between the different internal states of the molecules. This work aims at studying the population of the internal states of the nitrogen molecules and the time evolution of the internal energy modes in order to construct a model for atmospheric re-entry conditions. Different assumptions will be made in order to quantify the free electron temperature. In literature, this temperature is often chosen to be equal to the translational temperature. This hypothesis will be discussed and compared to a new model that compute the electron temperature based on the conservation the free electron energy.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Aerospace Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Heritier, Kevin

Contributors dc:contributor

• Panesi, Marco

• Chemical modeling of atmospherical re-entry conditions
• Kinetics
• The State-to-State Vibrational and Rotational kinetics of the nitrogen mixture is modeled
• Computational fluid dynamics (CFD)
• Computational methods for modeling hypersonic reactive flows
• Chemistry

Statement dc:rights

• Copyright 2014 Kevin Heritier

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/49582

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/49582