Laser Systems for High-Speed Measurements of Velocity, Temperature, Pressure, Species Concentrations, and UV-Visible Emission Spectra in Hypersonic Flows
Abstract
The Nonequilibrium Thermodynamics Laboratory and Gas Turbine Laboratory at the Department of Mechanical and Aerospace Engineering, Ohio State University (OSU), and University of Dayton Research Institute (UDRI) request instrumentation in support of a research program “Energy Transfer Processes in Nonequilibrium Hypersonic Flows�. The first objective of the proposed laser diagnostic measurements is the detailed characterization of a hypersonic flow field over a model in the test section of the OSU Mach 6 shock tunnel facility, including time-resolved, spatially resolved measurements of the flow velocity, static temperature, and static pressure. This will be accomplished by (i) single-shot, high sampling rate (up to 100 kHz) Femtosecond Laser Electronic Excitation Tagging (FLEET) velocimetry; (ii) single-shot, high sampling rate (1 kHz) fs-ps Coherent Anti-Stokes Scattering (CARS), with the temperature inferred from the pure rotational N2 CARS spectra and pressure inferred from the isolated, pressure-broadened spectral line shapes. The second objective is the time-resolved, low uncertainty measurements of the species controlling the UV emission and ionization behind hypersonic shocks, metastable (“dark�) excited electronic state of nitrogen (N2(A3sum)), nitric oxide (NO), and dominant molecular ion (NO+), as well as the UV-visible emission spectra in the UDRI shock tube facility, behind the Mach 8-13 incident shock. This will be done by (i) multichannel near-IR and mid-IR Laser Absorption Spectroscopy, using rapidly tunable, Distributed Feedback (DFB) lasers with MHz bandwidth IR detectors, and (ii) UV-visible emission spectroscopy using a spectrometer with an intensified MHz framing rate camera, with microsecond time resolution.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 22, 2024
- Source ID
- FA95502310002
Entities
People
- Igor Adamovich
Organizations
- Air Force Office of Scientific Research
- Ohio State University
- United States Air Force