Recirculation zone characteristics research on a sudden expansion swirl burner for DPF regeneration

Abstract

Based on the autonomously designed sudden expansion swirl burner and combined with the characteristics of diesel particulate filter (DPF) regeneration, fitting geometric parameters and values were determined with the orthogonal experimental design method. And the effects of main geometric parameters such as the sudden expansion ratio, length‐diameter ratio and position of air supply pipe on main evaluation indexes of the recirculation zone characteristics were studied with CFD. Results showed that with the geometry of sudden expansion ratio 2.0 and length‐diameter ratio 2.1 and air supply pipe located in the middle of the combustion chamber, the length of the recirculation zone in the center could be increased greatly; in order to increase the reattachment length, the sudden expansion ratio should be 1.5–2.0 and the length–diameter ratio should be larger and the air supply pipe should be closer to the fuel spray nozzle; and the swirl intensity was mainly depended on the length–diameter ratio, which could be effectively enhanced when the length–diameter ratio ranged from 2.1 to 2.4. It provides beneficial references for the research of complex flow field in sudden expansion swirl burner and porous medium. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018

Diesel particulate filter regeneration mechanism of modern automobile engines and methods of reducing PM emissions: a review

“…Active regeneration methods can be divided into two categories: fuel combustion (Fu et al 2018 ) and electrical equipment (electric heating (Zhong et al 2019 ) or microwave (Kurien et al 2020a )). The most convenient choice is that the diesel is used as active renewable energy (Fu et al 2018 ). The exhaust temperature will be increased by the additional fuel combustion.…”

“…The additional fuel enhances the reaction in the DOC, which in turn increases the temperature at the DOC outlet. The other technology is that the fuel was inject directly into the DPF and ignite additional fuel oxidation particles through the flame burner (Fu et al 2018 ). Both methods need to accurately control the heat balance of regeneration.…”

“…The regeneration process continues until the soot in the DPF is completely oxidized to CO or CO 2 . Pressure sensors and temperature sensors monitor the regeneration process in real time, which is conducive to discovering abnormal regeneration phenomenon in time (Fu et al 2018 ). The special sudden expansion structure can produce local reflux phenomenon, causing the combustible gas to roll into the flame, which is conducive to ignition stability.…”

“…For the open system, the oil-air mixing and combustion are easily affected by the fluctuation of air supply and combustion, which is not conducive to the stability and continuity of regeneration. Although this phenomenon has been improved by geometric optimization (Fu et al 2018 ) and the use of advanced nozzles (Yu et al 2021 ). In addition, the low combustion peak of alternative fuels has a great potential in active regeneration.…”

“…The traditional active regeneration is powered by an external device, and the captured particulate matter is oxidized by increasing the exhaust temperature. The specific heating technologies include fuel injection combustion (Fu et al 2018 ), electric heating (Presti et al 2013 ) and microwave (E et al 2019b ).…”