Session: Technical Posters

Paper Number: 110505

110505 - What Is the Best Configuration of Sampling Capillary for Fast-Spacims in Catalytic Monoliths? 

SpaciMS is an analytical technique based on mass spectrometry that provides spatially resolved measurements of transient species concentrations in catalytic monoliths by inserting a thin sampling capillary directly into one of the monolith channels. SpaciMS is often used to identify the reaction sequence and kinetics. In most cases, it is preferred to measure the concentration that is averaged over the channel cross-section and represents well the situation in a free channel.

There exist two effects that may lead to measuring different concentration values. First, the capillary blocks certain part of the channel, slows down the flow and increases the residence time in the sampled channel, which results in a higher conversion of the exhaust gases in comparison to the unobstructed channels. This effect is more important for thicker capillaries but can be minimized by setting proper sampling rate that may compensate the increased resistancefor the channel flow. The second issue may arise with very thin capillaries that sample local concentration, usually near the wall coated with the catalytic material as the capillary lies in the channel corner. Such a measurement may also provide higher than average conversion due to the radial concentration gradient in the channel.

The aim of this research is to use a custom, fully 3D, non-isothermal computational fluid dynamics (CFD) solver to simulate the SpaciMS experimental set up, quantify these effects and identify suitable capillary and sampling rate configurations that provide measurements close to the channel-averaged concentrations in an unobstructed channel. The simulations are confronted with the measured data from lab reactor, using CO oxidation as a test reaction.

Presenting Author: William Partridge Oak Ridge National Laboratory

Presenting Author Biography: Bill Partridge (William Powell Partridge, Jr.) is Distinguished Research Staff at Oak Ridge National Laboratory in the Fuels Engines and Emissions Research Center, and a graduate of the University of Tennessee (BSME 1988, MSME 1990) and Purdue University (PhD 1995). He has over twenty five years of experience developing and applying advance diagnostics based on a wide range of technologies including laser-induced fluorescence (LIF) and planar LIF, absorption, Raman, multi-photon spectroscopy, holographic interferometry, mass spectrometry, phosphor and organic-sensor fiber-optic probes and pyrometry. Dr. Partridge has developed numerous advanced analytical techniques for transient species and temperature distributions, and has applied these for broad research applications including fundamental heat transfer and combustion studies, automotive catalysis, engine systems and combustion, fuel reformers, PEM fuel cells, non-thermal plasma reactors, convective cooling and biological photodynamic therapy. These broad development and application activities demonstrate Bill’s rich experience and capability for advancing multidisciplinary research. He has forty eight archival peer-reviewed publications, twenty one invited or keynote lectures, nine patents and one commercially licensed technology related to these diagnostics, in addition to numerous book chapters, non-archival publications and technical reports. He is inventor and principal developer of the SpaciMS (Spatially Resolved Capillary Inlet Mass Spectrometry), EGR Probe, and Fuel-in-Oil (FiO) diagnostics; both SpaciMS and FiO have been commercialized by Hiden Analytical and Da Vinci Emissions Services, respectively, and were recognized with 2008 and 2013 R&D100 Awards as being among the top 100 technology products of the year.