10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Particle Measurement Under High Pressure Conditions on a Combustor Test Rig
Frank G. Bachman, TRISTAN REINISCH, Bill Silvis, Richard W. Frazee, Alexander Bergmann, GE Aviation
Abstract Number: 865 Working Group: Instrumentation
Abstract Until now, the only fundamental aerosol measurement approach available for an aviation turbine engine involves aerosol measurements taken at the exit plane of the aviation engine via fundamental particle measurement techniques. As the non-volatile aerosol measured at the exit plane of an aviation engine originates in, and is generated by, the combustor, it is highly desirable to be able to measure the aerosol at the exit plane of the combustor. The scientific drive, along with activities in the emissions legislation arena for aircraft engines, motivated us to investigate a particle measurement approach allowing for the measurement of the aerosol at the combustor exit plane.
We introduce a pressure reduction unit which is optimized for particle measurements applicable to the emission characteristics at the aviation turbine engine combustor exit plane. Particle loss mechanisms are considered and countermeasures reduce their influence. Particle Number Concentration, Particle Mass Concentration and Filter Smoke Number are the quantities used for characterization.
The pressure levels in a combustor of an aircraft turbine engine are much higher than those encountered in other typical combustion processes (e.g. internal combustion engines), where particle emissions are relevant and regulated. The commonly used measurement equipment is not designed to operate under such conditions. Thus, there is a need to reduce the pressure of a combustor exit plane aerosol sample to ambient conditions. A pressure reduction unit with critical flow elements was engineered and characterized on a combustor test rig at GE Aviation.
The pressure independent results for non-volatile particle matter were compared to a proprietary Filter Smoke Number based system, developed by GE Aviation, which is specifically designed to measure at sampling system pressure levels above ambient pressure. In this study, we prove that the pressure reduction unit for particle measurement equipment operating at ambient pressure conditions fulfills all our requirements. We also prove that further measurement results are reproducible and comparable throughout the typically encountered operating fuel-air-mass ratio range of the combustor. This gives the opportunity to use the results for further combustor development, specifically the ability to design the combustor to specific nvPM requirements. To show also that this instrument can be used to investigate the emitted soot particles with respect to morphology, we took samples for Raman spectroscopy. The results show highly graphitized carbon with sp² hybridization which is typical for soot particles produced under high pressure conditions.