Numerical analysis of temperature characteristics in diesel particulate filter under transient conditions
1. School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang， Jiangsu 212013, China； 2. College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China； 3. School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
Abstract：During the use of diesel particulate filter（DPF）, the thermal shock of the exhaust can make a large temperature gradient, resulting in thermal stress damage. To avoid the thermal damage of DPF， the DPF temperature transfer model was established， and the effects of flow rate, cell per square inch(CPSI), filter length and soot deposition on the temperature characteristics were investigated. The results show that the flow rate has obvious effect on the temperature characteristics of DPF.When the flow rate is increased from 173 kg·h-1 to 1 072 kg·h-1, the axial temperature gradient is decreased by 56.2%. When the CPSI is increased from 100 to 300, the delay time is reduced by 38.36%. When the length of the filter is increased from 270 mm to 630 mm, the axial temperature gradient extreme value is reduced from 1 465.89 K·m-1 to 734.78 K·m-1. When the soot deposition contents are 0, 1.0, 2.2, 4.0 and 8.0 g·L-1, the axial temperature gradient extreme values are 1 465.88, 1 478.62, 1 493.24, 1 521.16 and 1 621.21 K·m-1，respectively. The increase of soot loading can lead to an exponential increase in the extreme value of temperature gradient, which aggravates the local temperature accumulation and enhances the risk of thermal stress damage.
