The capability of taking non-intrusive species measurements in a jet plume of a modified mid-size low by-pass aero-engine running on a sea level test bed at several thrust levels was demonstrated. Also conventional intrusive measurements were performed with a spatially resolved method using a traversing single-point sampling probe which fulfills ICAO standards. The FTIR spectrometry measurements included both emission and absorption mode with a multi-path reflection compartment as well as the single emission mode. Due to the lack of a common/unique definition for the exhaust plume diameter it was found that the column density was the best measure to compare the different techniques. The FTIR engine measurement results for CO₂, CO, and NO have been proven to be in agreement with the intrusive data within plus or minus 30%. Several error sources during the radiometric radiance calibration were identified which lead to uncertainties in the FTIR retrievals, namely (1) incomplete knowledge of the optical surface emissivities, (2) incomplete knowledge and inhomogeneities of the optical surface temperature, and (3) undefined instrumental drifts and non-linearities during the calibration.

Date Published: 16 September 1999
PDF: 6 pages
Proc. SPIE 3821, Environmental Sensing and Applications, (16 September 1999); doi: 10.1117/12.364205

Published in SPIE Proceedings Vol. 3821:
Environmental Sensing and Applications
Michel R. Carleer; Moira Hilton; Torsten Lamp; Rainer Reuter; George M. Russwurm; Klaus Schaefer; Konradin Weber; Klaus C. H. Weitkamp; Jean-Pierre Wolf; Ljuba Woppowa, Editor(s)