COHERENT ANTI-STOKES RAMAN SCATTERING (CARS) SYSTEM FOR TEMPERATURE AND SPECIES CONCENTRATION MEASUREMENTS
Abstract
The University of Texas at Arlington houses a unique combination, in the academic panorama, of experimental facilities dedicated to fundamental research with focus on relevant aspects of lowspeed, high-speed, high-enthalpy flows, and high-temperature gas/surface interaction. In particular, the Aerodynamics Research Center was awarded a grant by the Office of Naval Research and the ]Defense A dvanced Research Projects Agency to develop, based on the previous 1.6MW Arc-Heated Wind Tunnel (AHWT) system, a national-level rese arch facility for hightemperature materials development and characterization in support of DoD programs on ultra-high temperature ma terials for hypersonic technologies. The only university-operated, large-scale, archeated wind tunnel in the country capable of high -impact pressures and high-shear. The facility has been inaugurated in June 2019. For more than 50 years, arc-jet testing has served as primary basis for characterizing ThermalProtection Systems (TPS) in support of material development and response model validati on. Arc-Jet facilities provide the only ground-based means of simulating hypersonic heating rates (entry, reentry, hypersonic cruis e) in a reacting flow environment under flight relevant durations. Arc-jettesting provides data for detail material response models that can reduce uncertainty and themagnitude of thickness margins. Arc-jets are also essential to investigate mechanical failure m odesincluding erosion, spallation, and losses related to shear effects. The major current limitation of Arcjettesting is related t o the uncertainty of the flow conditions. Although arc-jet tests are indicative ofhow well a material will perform in extreme aerot hermal heating environments, it has not been possible to directly relate arc-jet test results to flight applications. The main obsta cle has been an inability to determine the total enthalpy of the nonequilibrium arc-jet flow, and its distribution among kinetic, th ermal, and chemical modes. This proposal is for a laser-based diagnostic system to be an integral part of the ONR-UTA archeated plas ma wind tunnel spectrum of capabilities. Specifically, the proposed equipment will augment the currently available femtosecond laser system (used for fs-TALIF and FLEET measurements) allowing to perform Coherent Anti-Stokes Raman (CARS) spectroscopy. Thistechniqu e enables quantitative measurements of the nonequilibrium temperatures of multiplemolecular species thus revealing the thermal mode of the flow total enthalpy. With the proposed capabilities, the new arc-heated wind tunnel will constitute a national asset and a u nique platform in support of the Department of Defense programs on aerothermodynamics andultra-high temperature materials for hyper sonic technologies. Participating students and post-docs will be able to gain unique scientific and technical expertise in associate d disciplines relevant to the DOD.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 07, 2021
- Source ID
- N000142112846
Entities
People
- Luca Maddalena
Organizations
- Office of Naval Research
- United States Navy
- University of Texas at Arlington