Characterization of Mixing and Ignition Effects in Flow-Reactor Facilities Using a Particle Method

摘要

Stationary power plants utilizing integrated gasification combined cycle (IGCC) technologies are considered to be a viable option for clean electricity generation. Considerable design challenges still exist that are attributed to the IGCC-operating conditions and requirements for the stable combustion of syngas and high hydrogen content (HHC) fuels. Recent investigations have indicated discrepancies between measurements and simulations of the ignition delay for syngas-mixtures at high-pressure and low-temperature conditions. The objective of this study is to characterize effects of turbulence and flow-field inhomogeneities on the mixing and ignition-dynamics in flow-reactors. To this end, an idealized flow-reactor is considered and a particle method is used to describe the mixing, induction, and subsequent ignition of the reactants. Utilizing this model, parametric studies are performed to quantify effects of flow-field and scalar inhomogeneities on the ignition-process for practically relevant temperature and pressure conditions. Results suggest that the unsteady velocity field affects the ignition location and residence time in the flow-reactor. Stochastic events, such as the formation of localized ignition spots upstream of the main ignition front could be observed in the simulation. Their impact on the global ignition dynamics needs to be evaluated in further research activities.