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Abstract
Combustion at the microscale shows an immeasurable potential in the fields of energy utilization and microelectromechanical systems (MEMS) due to its novel combustion characteristics. Studying the mechanism of this kind of combustion is of great significance for deepening the understanding of microcombustion phenomena and designing related devices. In this article, the non-premixed combustion of H2/O2 in a two-dimensional Y-shaped microchannel with a height of 10 μm was numerically studied using the direct simulation Monte Carlo (DSMC) method. The total collision energy (TCE) model and a kinetic mechanism including six species and seven reversible reactions were employed. Predicted distributions of velocity, temperature, heat flux, and components inside the microchannel are presented and analyzed. Influences of the Knudsen number and wall surface conditions on the combustion characteristics are discussed. The results show that the exothermic reaction mainly takes place in the junction area of the branch channels and in the first half of the main channel, and the wall heat flux at the microscale is much higher than that at the conventional scale. This is helpful to effectively heat and ignite the gaseous H2/O2 mixture. Moreover, the conversions and distributions of individual components in the flow field are mainly controlled by the chemical kinetics; the Kn number and different wall conditions have a sophisticated influence on the combustion process.