Comparison of remote sensing techniques for measurements of aircraft emissions indices at airports

摘要

The emission indices of aircraft engine exhausts were measured at airports by non-intrusive optical measurements by FTIR emission spectrometry at the engine nozzle exit as well as by FTIR absorption spectrometry and DOAS (Differential Optical Absorption Spectrometry) behind the aircraft. Two measurement campaigns were performed to compare these different measurement methods. A kerosene-powered burner was operated in such a way that the different methods were applied for the exh aust gas investigations during the same time and at nearly the same exhaust gas volume. The burner was built with a nozzle exit diameter of 37 cm and a power of about 150 kW. Fresh air is pumped into the burner tube by a fan. Calibration gases of CO and NO (pure gases) were added in different amounts to vary the concentration of these gases in the exhaust. The sampling probe of the intrusive measurement system was installed in the centre of the exhaust stream near the exhaust exit for measurements of CO_2, CO, NO, NO_2, UHC, SO_2 and O_2. An APU (GTCP36-300) in a test bed was used in the same way. CO was mixed into the exhausts near the nozzle exit. The passive FTIR instrument was operated in the test bed using special noise and vibration isolation. The open-path instruments were installed at the chimney exit on the roof of the test bed building. The deviations between the different measurement methods were of the order of +-10 up to +-20 %.