Regeneration Analysis Under Different Exhaust Gas Thermal Conditions

Abstract

A refinement of the honeycomb trap model developed by the authors for analyzing the temperature history of the trap channels during the regeneration period is presented. The first results obtained, shown in previous papers [1, 2], encouraged the authors to improve the model in order to account for the heat transfer not only along the channel length, but also in the radial direction. In order to achieve this objective, a control volume approach was used to simulate the soot regeneration in all contiguous channels along the axial and radial directions of the monolith, and to determine the wall temperature and soot oxidation as a function of time. Different thermodynamic conditions of the exhaust gas at the trap inlet were considered in order to examine the effects of cold regeneration. For the same soot amount accumulated in the trap, the soot burnup time and temperature history depend on the inlet temperature. In addition to varying the gas initial conditions, the effects of the amount of soot collected and its radial distribution in the channels, before the regeneration process takes place, were also considered in order to predict the wall temperature rise and the soot oxidation rate. The results show the temperature peak values and their location inside the trap, and permit estimation of the conditions under which the trap temperature can reach unbearable values.