Characterization of the Soot Deposition Profiles in Diesel Engine Exhaust Gas Recirculation (EGR) Cooling Devices Using a Digital Neutron Radiography Imaging Technique

A non-destructive neutron radiography technique was used to measure the thickness of diesel soot deposited in the tubes of exhaust gas recirculation (EGR) cooling devices. Measurements were performed to characterize the fouling in single-tube and three-tube devices for laminar and turbulent flows. Measurements were also performed to characterize the effect that the design of the inlet header had on the deposition characteristics in the device. The analysis of the neutron images showed that the soot deposition in the single-tube device occurred at a faster rate for a turbulent flow than for a laminar flow. The deposition thickness decreased along the tubes for both flow regimes. More soot deposited in the center tube of the three-tube bundle for the expansion angle 45° inlet header suggesting there was an uneven distribution of the exhaust gas flow in the tube bundle. For the device with the expansion angle 60° inlet header the soot was approximately more evenly distributed along the tubes.