AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
System for the Absolute Calibration of Black Carbon Mass Concentration Measurement Instruments
KEVIN THOMSON, Fengshan Liu, Gregory Smallwood, National Research Council Canada
Abstract Number: 702 Working Group: Instrumentation and Methods
Abstract Previously, it has been shown that real time mass concentration measurement instruments such as those based on photo-acoustic methods or laser-induced incandescence show very good linearity with black carbon (BC) concentration. However, these instruments either intrinsically require absolute calibration or benefit in terms of improved measurement accuracy when calibrated against an absolute reference for Black Carbon.
A system for the absolute calibration of black carbon mass concentration measurement instruments has been developed which uses the elemental carbon component of a thermal/optical filter analysis as the basis of calibration. The source of black carbon is an inverted flame burner which produces steady and repeatable exhaust concentration of about 70 mg/m³ with a low organic carbon concentration. A sample is extracted from the exhaust and diluted using a series of dilutors to achieve concentrations in the range of 50 µg/m³ to 1000 µg/m³. A multi-port splitter splits the flow over multiple mass concentration instruments to be calibrated as well as to a filter for the acquisition of sample for thermal/optical analysis.
The calibration system has been applied for the calibration of 7 mass concentration measurement instruments which were used in an SAE-E31 civil aviation aircraft engine non-volatile particulate matter (nvPM) measurement campaign conducted in Switzerland in summer 2013. The SAE E-31 Aircraft Exhaust Emissions Measurement Committee has been tasked with designing and documenting a sampling system and instrumentation for measuring aircraft engine nvPM mass and number emissions, in anticipation of new certification requirements aimed at limiting the emissions of BC. This will be used in the development of a new international standard and a recommended practice which will address black carbon emissions from the aviation sector.