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Single Pulse Broadband Nitrogen CARS Measurements in the High Enthalpy, Hypersonic Flow Field of L3K at Temperatures up to 5800 K

Fischer, Michael and Koch, Uwe and Esser, Burkard and Guelhan, Ali and Magens, Eggert and Mueller, Martin (2011) Single Pulse Broadband Nitrogen CARS Measurements in the High Enthalpy, Hypersonic Flow Field of L3K at Temperatures up to 5800 K. 7th European Symposium on Aerothermodynamics for Space Vehicles, 9-12 May 2011, Brugge, Belgium.

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Abstract

Single pulse broadband coherent anti-Stokes Raman scattering (CARS) was used to measure the thermal non-equilibrium flow properties in the high enthalpy hypersonic flow field (11.8 MJ/kg, 5800 K) of the arc heated facility L3K in Cologne. Nitrogen CARS was applied in the free stream flow at 64 mbar and in the vicinity front of a probe body at app. 1 bar. At both conditions a distinct thermodynamic non-equilibrium was found, but vice versa for both positions. In the free stream the vibrational temperature was about 920 K higher than the rotational temperature, which should be in equilibrium with the translational movement within a few collisions. Downstream the shock front (e.g. between shock and body) a rotational temperature exceeded the vibrational temperature by about 1100 K. The CARS measurements on nitrogen were chosen because of the high thermal stability of molecular nitrogen, resulting in a mass fraction of still 76 %. Additionally, the spectral simulation of nitrogen CARS spectra is well developed. The aim of this study was to test the feasibility to perform time resolved CARS temperature measurements on nitrogen which is the main molecular component of the flow. Details of the experimental set up and results are presented.

Item URL in elib:https://elib.dlr.de/74297/
Document Type:Conference or Workshop Item (Speech, Paper)
Title:Single Pulse Broadband Nitrogen CARS Measurements in the High Enthalpy, Hypersonic Flow Field of L3K at Temperatures up to 5800 K
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Fischer, Michaelmichael.fischer (at) dlr.deUNSPECIFIED
Koch, Uweuwe.koch (at) dlr.deUNSPECIFIED
Esser, Burkardburkard.esser (at) dlr.deUNSPECIFIED
Guelhan, Aliali.guelhan (at) dlr.deUNSPECIFIED
Magens, Eggerteggert.magens (at) dlr.deUNSPECIFIED
Mueller, Martinmartin.mueller (at) dlr.deUNSPECIFIED
Date:2011
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:CARS, coherent anti-Stokes Raman scattering, laser spectroscopy, re-entry aerodynamics, high enthalpy flow, temperature measurement
Event Title:7th European Symposium on Aerothermodynamics for Space Vehicles
Event Location:Brugge, Belgium
Event Type:international Conference
Event Dates:9-12 May 2011
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Propulsion Systems (old)
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation Methods (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Supersonic and Hypersonic Technology
Institute of Propulsion Technology > Engine Measurement Systems
Deposited By: Willert, Dr.phil. Christian
Deposited On:23 Jan 2012 09:20
Last Modified:27 Aug 2012 08:57

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