ESA / ESTEC, CHEF, Technical note on test results TN5B, V 1.1 Part B: Results of CARS measurements

Abstract

One of the main objectives of this ESA’s Technological Research Programme (TRP) “Characterization of High Enthalpy Facilities and Streamlining of Calibration and Tests (CHEF)” is application of non-intrusive measurement techniques to the flow field in the arc heated facility L3K Cologne. Part B of the report describes the results of the CARS (coherent anti-Stokes Raman scattering ) measurements performed in the frame of CHEF in summary and includes a description of the final optical-set-up for CARS measurements at L3K. The temperature and relative density of N2 molecules were measured in the centre of the free stream at reduced pressure and in the shock region. In addition (for the first time) temperature measurements were performed in the centre of the settling chamber of L3K at 3.8 to 5.9 bar, and temperatures up to 6550 K, to characterize the entrance conditions of the nozzle. The results from the settling chamber are preliminary particularly regarding the data filtering necessary as a consequence of possible mixed temperature spectra in the settling chamber. Nevertheless the performed data evaluation is state of the art.