Combustion Characteristics of Sinusoidal-Shaped Walls with Catalyst Segmentation in Micro-Combustors for Micro-Thermophotovoltaic Application

Abstract

The combustion characteristics of micro-combustors significantly impact the performance of micro-thermophotovoltaic (MTPV) systems. This study aims to investigate the effects of sinusoidal-shaped walls and catalyst segmentation on flame stability and combustion performance in a micro-combustor by using numerical methods. The numerical simulation with detailed gas-phase and surface reaction mechanisms is reliable, as the results of numerical simulation align with experimental data. The results show that the interplay between flame stability and sinusoidal-shaped walls is crucial, particularly because of the cavities formed by the sinusoidal-shaped walls of the micro-combustor. The gas-phase ignition position of the sinusoidal-shaped wall combustor moves upstream by 0.050 m compared to the planar-wall combustor, but the flame is stretched. The catalyst segments coated on the crest can shorten the flame length and increase the average temperature by a maximum 62 K, but delay the gas-phase ignition. Conversely, catalyst segments coated on the trough can advance ignition, but this results in flame elongation and a decrease in the average temperature. The rational combination of catalyst segmentation and sinusoidal-shaped walls facilitates moving the ignition position upstream by a maximum of 0.065 m while substantially reducing the length of the combustor required for complete fuel conversion by more than 60%. These attributes are highly beneficial for improving efficiency and minimizing the length of the micro-combustor for MTPV application.