Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Byron Jones / Contamination of aircraft bleed air with engine oil and/or hydraulic fluid results in a “fume event” in the aircraft cabin. Exposure to contaminated bleed air may have acute and/or chronic adverse health effects based on the intensity of various chemicals which are released during such a fume event. ASHRAE Standard 161, Air Quality within Commercial Aircraft, includes a requirement for bleed air sensors to detect contamination from lubricating oil. One potential approach to meeting this requirement is through particle detection. In the research reported here, the end goal is to provide data needed to develop an automated detection apparatus for contaminated bleed air through oil particle detection. Consequently, the type and concentration of different chemicals as well as the number and size distribution of particles were determined for bleed air with different rates of contamination under various turbine engine operating conditions. Multiple fume events were simulated by using a four-part experimental program to develop a detailed characterization of particles that result when bleed air is contaminated with lubricating oil. Test results show that oil contamination in the compressor will result in a fog of very fine droplets in the bleed air under most operating conditions. With moderately high contamination rates at elevated power levels (high bleed air temperature) the concentration distribution and particle size does not vary much with power (temperature) and generally depends on the rate of contamination. Moreover, at elevated power levels, the peak particle concentration takes place in the range of 50 to 70 nanometers and the bulk of the particles form at less than 150 nanometers. At very low contamination rates very ultrafine particles can be generated in the size of 10 nanometers or less. As a result, detection is needed for a range of sizes ranging from about 100 nanometers to 10 nanometers.

Doctor of Philosophy / Department of Mechanical Engineering / Steven J. Eckels / Byron W. Jones / Poor air quality in commercial aircraft cabins can be caused by volatile organophosphorus (OP) compounds emitted from the jet engine bleed air system during smoke/fume incidents. Tri-cresyl phosphate (TCP), a common anti-wear additive in turbine engine oils, is an important component in today’s global aircraft operations. However, exposure to TCP increases risks of certain adverse health effects. This research analyzed used aircraft cabin air filters for jet engine oil contaminants and designed a jet engine bleed air simulator (BAS) to replicate smoke/fume incidents caused by pyrolysis of jet engine oil. Field emission scanning electron microscopy (FESEM) with X-ray energy dispersive spectroscopy (EDS) and neutron activation analysis (NAA) were used for elemental analysis of filters, and gas chromatography interfaced with mass spectrometry (GC/MS) was used to analyze used filters to determine TCP isomers. The filter analysis study involved 110 used and 74 incident filters. Clean air filter samples exposed to different bleed air conditions simulating cabin air contamination incidents were also analyzed by FESEM/EDS, NAA, and GC/MS. Experiments were conducted on a BAS at various bleed air conditions typical of an operating jet engine so that the effects of temperature and pressure variations on jet engine oil aerosol formation could be determined. The GC/MS analysis of both used and incident filters characterized tri-m-cresyl phosphate (TmCP) and tri-p-cresyl phosphate (TpCP) by a base peak of an m/z = 368, with corresponding retention times of 21.9 and 23.4 minutes. The hydrocarbons in jet oil were characterized in the filters by a base peak pattern of an m/z = 85, 113. Using retention times and hydrocarbon thermal conductivity peak (TCP) pattern obtained from jet engine oil standards, five out of 110 used filters tested had oil markers. Meanwhile 22 out of 74 incident filters tested positive for oil fingerprints. Probit analysis of jet engine oil aerosols obtained from BAS tests by optical particle counter (OPC) revealed lognormal distributions with the mean (range) of geometric mass mean diameter (GMMD) = 0.41 (0.39, 0.45) [mu]m and geometric standard deviation (GSD), [sigma][subscript]g = 1.92 (1.87, 1.98). FESEM/EDS and NAA techniques found a wide range of elements on filters, and further investigations of used filters are recommended using these techniques. The protocols for air and filter sampling and GC/MS analysis used in this study will increase the options available for detecting jet engine oil on cabin air filters. Such criteria could support policy development for compliance with cabin air quality standards during incidents.