Synergy Analysis of the Influence of the Connection Cone on the Thermal Distribution during Regeneration

Abstract

Diesel particulate filters (DPF) are typically used for particle filtration in vehicle exhausts after a treatment system. The monolith inside a DPF is a symmetrical column structure, frequently an axisymmetric cylinder structure where filtration and regeneration occur. Due to the complex structure before the symmetric monolith, the internal particle distribution is not uniform, which leads to an uneven temperature change when regeneration occurs. During thermal regeneration, the temperature field inside a DPF is affected by the particle load, exhaust temperature and exhaust flow. The relationship between the temperature gradient and velocity vector is also a key factor influencing regeneration performance. Based on the particle-loading test method, a bench for thermal distribution testing during regeneration was built. Via experiments and simulations, the temperature field in an axisymmetric monolith during particle combustion given an uneven particle distribution was analyzed. Through field synergy analysis of the temperature and velocity fields in the monolith, the influence of connection cones with different structures on heat transfer enhancement was studied. The results indicated that compared with a monolith with a conventional linear cone, the radial temperature gradient is 1.1 °C/mm lower, the area of enhanced regeneration is larger, and the regeneration rate is improved in the monolith with a streamlined cone.