AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Investigating the Distribution of Mass and Mobility Diameter of Lab-Scale, Flare-Generated Soot Using Tandem CPMA-SMPS Measurements
TIMOTHY SIPKENS, Mohsen Kazemimanesh, Melina Jefferson, Matthew Johnson, Jason S. Olfert, Steven Rogak, University of British Columbia
Abstract Number: 723 Working Group: Combustion
Abstract Soot contributes significantly to the anthropogenic radiative forcing responsible for climate change and to human respiratory health. The morphology of soot aggregates contributes to their impact in these roles. In response, researchers are increasingly using tandem measurements of soot mass, using devices such as the aerosol particle mass analyzer (APM) and the centrifugal particle mass analyzer (CPMA), and electromobility, using devices such as the differential mobility analyzer (DMA), to determine morphological parameters of soot. These parameters can include the effective density, shape factor, and mass-mobility exponent. However, increasingly detailed information about the soot can be obtained by considering the two-dimensional mass-mobility distribution. This requires novel approaches to deconvolving the instrument transfer functions, and the current work examines a range of candidate techniques to perform this task, including Twomey-type schemes, Tikhonov regularization, and a Bayesian approach. In this work, these approaches will be applied to soot generated from a buoyancy-driven, turbulent, lab-scale flare over a range of fuel compositions that represent real global flare gases, that is predominantly methane with varying levels of C2-C7 alkanes, nitrogen, and carbon dioxide. The resultant mass-mobility distributions will not only give trends in quantities like the average effective density of the particles and the shape factor as a function of fuel type but will also give an indication of how the distribution of these various quantities evolve with changes in the fuel. The results of this study can be used to develop more accurate statistical models of soot aggregate formation and their relation to the local conditions within flares.