Mitigation of Soot Deposition in Exhaust Gas Recirculation Coolers Using a Spiral Insert

Abstract

In diesel engines, the emission of nitrogen oxides can profoundly be controlled by using exhaust gas recirculation (EGR) coolers. Nevertheless, the deposition of unwanted materials, in form of primarily particulate matter and hydrocarbons, causes a major hurdle to the durability of such devices. In this study, a novel technique, i.e., a spiral insert, has been developed to mitigate particulate fouling in tubular EGR coolers. It is made of a helical rotating blade which is inserted inside the tubes of EGR coolers, and it rotates around its axis under the force of entering gas flow. As the blade rotates, it wipes out the deposit. An EGR experimental setup has also been used to examine how effective the spiral insert is in suppressing particulate fouling for two different gas velocities with and without using the insert. With no insert, the deposition was severe, fast, and continuous. For the latter, though, it was first very slow, and second, the fouling resistance was four times lower to that of no insert. No sign of any deposit was also observed on the insert after fouling runs. Despite the promising results, the insert requires further development so it can rotate at the low gas velocities.

Effect of soot particle deposition on porous fouling formation and thermal characteristics of an exhaust gas recirculation cooler

“…However, the fouling problem in EGR coolers has been an engineering challenge ever since those systems have been introduced. It has been shown that the fouling in EGR coolers reduces their thermo-hydraulic performance over time [3][4][5][6]. Numerous studies have been devoted to investigating this problem during the previous two decades.…”

“…The exhaust gas is assumed to contain only soot particles and condensation of SOF is neglected which is justifiable for large wall temperatures[8].V. The removal mechanism is ignored because of the low-flow EGR considered[4,11].VI. The thermophoresis is considered as the dominant mechanism for deposition of nano-sized soot particles[11][12][13].VII.…”