Analysis of aircraft exhausts with Fourier-transform infrared emission spectroscopy

摘要

Because of the worldwide growth in air traffic and its increasing effects on the atmospheric environment it is necessary to quantify the direct aircraft emissions at all altitudes. In this study Fourier-transform infrared emission spectroscopy as a remote-sensing multi-component-analyzing technique for aircaft exhausts was investigated at ground level with a double pendulum interferometer and a line-by.] computer algorithm that was applied to a multilayer radiative transfer problem. Initial measurements were made to specify the spectral windows for traceable compounds, to test the sensitivity of the system, and to develop calibration and continuum handling procedures. To obtain information about the radial temperature and concentration profiles, we developed an algorithm for the analysis of an axial-symmetric multilayered plume by use of the CO↓(2) hot band at approximately 2400 cm↑(-1) Measurements were with several in-service engines. Effects that were due to engine aging were detected but have analyzed systematically in the near future. Validation measurements were carried out with a conventional propane gas burner to compare the results with those obtained with standard measurement equipment. These measurements showed good agreement to within -- 20% for the CO and NO↓(x) results. The overall accuracy of the system was found to be±30%. The detection limits of the system for a typical engine plume (380 ℃，φ= 50 cm) are below 0.1% for CO↓(2), ~0.7% for H↓(2)O. ～20 ppmv (parts per million by volume) for CO, and ～90 ppmv for NO. #1997 Optical Society of America