Impacts of feed temperature on propane ignition features in catalytic micro-burners

Abstract This study aims to conduct a numerical analysis of the ignition characteristics of homogeneous-heterogeneous (HH) combustion of propane in a Pt-catalyzed microburner, with a focus on elucidating the influence of feed temperature on the cold-start ignition process. To this end, a two-dimensional model is developed, incorporating one-step homogeneous and catalytic reaction mechanisms, within a parallel-plate microburner configuration. A series of transient simulations is performed by varying the feed temperature. The variations in ignition time, peak combustion temperature, and temperature profile of reactor’s outer wall are quantitatively analyzed. The numerical results demonstrate that the feed temperature has a notable impact on the ignition time. Specifically, when the feed temperature rises from 559 K to 590 K, the ignition time decreases by over 100 seconds. However, it has a minimal effect on the peak combustion temperature and the temperature profile of reactor’s outer wall. The maximum temperature increases by merely 32 K with the feed temperature rising from 559 K to 590 K. As the feed temperature increases, the initial energy carried by the premixed inlet gas mixture increases accordingly. Such an elevation reduces the time required to reach the ignition point and facilitates the acceleration of the reaction rate. Nevertheless, at a fixed inlet velocity, a reduction in the fuel mass flow rate generally leads to diminished combustion intensity due to limited fuel availability. The combined effect results in an unremarkable difference in the maximum temperature and the temperature distribution of the outer wall. These results offer an essential groundwork for optimizing the operation of catalytic microburners.