Asymptotic characteristics of particulate deposit formation in exhaust gas recirculation (EGR) coolers

The objective of this research is to shed some light into the asymptotic behavior of fouling process in EGR coolers based on a theoretical hypothesis that is verified experimentally. This is important for a successful simulation of particulate fouling in EGR coolers and to develop appropriate fouling mitigation approach. The experimental results showed that the development of fouling layer causes i) the thermal resistance of the fouling layer to increase as well as decreased temperature difference between the gas side and the fouling layer, which subsequently decreases the deposition rate, ii) the tube cross-sectional area to decrease thus the average gas-side temperature increases, consequently the gas velocity and deposit removal would increase. At a certain moment of time a balance occurs between the decreasing deposition rate and the increasing removal rate such that the fouling process ceases and an asymptotic behavior is approached.