TY - JOUR
T1 - Neutron tomography of exhaust gas recirculation cooler deposits
AU - Lance, Michael J.
AU - Bilheux, Hassina
AU - Bilheux, Jean Christophe
AU - Voisin, Sophie
AU - Sluder, C. Scott
AU - Stevenson, Joseph
PY - 2014
Y1 - 2014
N2 - Exhaust gas recirculation (EGR) cooler fouling has become a significant issue for compliance with NOx emissions standards. Exhaust gas laden with particulate matter flows through the EGR cooler which causes deposits to form through thermophoresis and condensation. The low thermal conductivity of the resulting deposit reduces the effectiveness of the EGR system. In order to better understand this phenomenon, industry-provided coolers were characterized using neutron tomography. Neutrons are strongly attenuated by hydrogen but only weakly by metals which allows for non-destructive imaging of the deposit through the metal heat exchanger. Multiple 2-D projections of cooler sections were acquired by rotating the sample around the axis of symmetry with the spatial resolution of each image equal to ∼70 m. A 3-D tomographic set was then reconstructed, from which slices through the cooler sections were extracted across different planes. High concentrations of hydrocarbon is necessary for imaging deposits and only those coolers which exhibited large organic fractions or hydrated sulfate phases were successfully characterized. Cooler plugging and the effect of internal cooler geometry on the deposit thickness and spallation were characterized. Results are discussed in relation to future performance gains expected to occur with new spallation neutron sources that will provide energy selectivity and higher spatial resolutions.
AB - Exhaust gas recirculation (EGR) cooler fouling has become a significant issue for compliance with NOx emissions standards. Exhaust gas laden with particulate matter flows through the EGR cooler which causes deposits to form through thermophoresis and condensation. The low thermal conductivity of the resulting deposit reduces the effectiveness of the EGR system. In order to better understand this phenomenon, industry-provided coolers were characterized using neutron tomography. Neutrons are strongly attenuated by hydrogen but only weakly by metals which allows for non-destructive imaging of the deposit through the metal heat exchanger. Multiple 2-D projections of cooler sections were acquired by rotating the sample around the axis of symmetry with the spatial resolution of each image equal to ∼70 m. A 3-D tomographic set was then reconstructed, from which slices through the cooler sections were extracted across different planes. High concentrations of hydrocarbon is necessary for imaging deposits and only those coolers which exhibited large organic fractions or hydrated sulfate phases were successfully characterized. Cooler plugging and the effect of internal cooler geometry on the deposit thickness and spallation were characterized. Results are discussed in relation to future performance gains expected to occur with new spallation neutron sources that will provide energy selectivity and higher spatial resolutions.
UR - http://www.scopus.com/inward/record.url?scp=84899564057&partnerID=8YFLogxK
U2 - 10.4271/2014-01-0628
DO - 10.4271/2014-01-0628
M3 - Conference article
AN - SCOPUS:84899564057
SN - 0148-7191
VL - 1
JO - SAE Technical Papers
JF - SAE Technical Papers
T2 - SAE 2014 World Congress and Exhibition
Y2 - 8 April 2014 through 10 April 2014
ER -