Molecular Energy Transfer Processes in Nonequilibrium Hypersonic Flows
Abstract
A program investigating nonequilibrium flows with substantial thermodynamic nonequilibrium isproposed, including the following thrusts:(I) Study of the mechanism of high-speed nonequilibrium flow manipulation by varying vibrational relaxation time. The approach includes loading of energy into molecular vibrational modes in the plenum of a nonequilibrium flow wind tunnel, energy transport with the flow to the test section, and its coupling to the flow at a desired location. The experiments will be done in nitrogen and air flows (up to M=5), with CO2 injection used to accelerate vibrational relaxation.(II) Study of O and N atom recombination kinetics in a high specific energy, pulsed excitation cell, monitoring time-resolved number densities of reactants (O and N atoms) and products (vibrational levels of the ground electronic state, O2(X3?,v) and N2(X1?,v), and excited electronic states, O2(a1?) and N2(A3?)), after the excitation. State-specific recombination / dissociation rate coefficients will be inferred using kinetic modeling.(III) Development of laser diagnostics for characterization of nonequilibrium flows, including (a) high frame rate CARS for measurements of N2 and O2 vibrational temperatures; (b) ps TALIF for measurements of O and N atom number densities in partially dissociated flows; and (c) Cavity Ring-Down Spectroscopy, to measure number densities of excited electronic states of O2 and N2 generated during atom recombination in partially dissociated flows.(IV) Further development and use of the state-specific kinetic model for analysis of stronglynonequilibrium, chemically reacting molecular gas mixtures. Incorporation into the model of highfidelity, state-specific vibrational relaxation / dissociation / recombination cross section setspredicted by quasiclassical trajectory calculations for oxygen and nitrogen.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2017
- Source ID
- FA95501710370
Entities
People
- Igor Adamovich
Organizations
- Air Force Office of Scientific Research
- Ohio State University
- United States Air Force