Investigation of flame structure and emission production: Combustion modeling of co-flow interaction with spray

Abstract

Using a validated computational approach, the present study examines the flame structure and emission production by spray combustion in an unconfined, swirl-free lab burner. Some species, such as acetylene, a precursor to the formation of polycyclic aromatic hydrocarbons, are generated within the fuel-rich region. A smaller area of the enclosed region reduces the mass concentration of emissive species. This can be accomplished by modifying the operating conditions, such as the spray characteristics, macro-flow velocity, and nozzle geometry. Increasing the co-flow velocity has a significant effect on transforming the flame structure from a single-reaction regime to a double-structure regime. The fuel-rich area shrinks as the co-flow velocity increases, resulting in a decrease in emissive species but a fall in total heat generation. In terms of air passage design, it appears that altering the air passage area has a noticeable impact on the flame structure, where a reaction zone can be established within the flame core. Depending on the equivalence ratio, the total heat generation and output emissions can be modified through the burner air passage improvement, resulting in a 90% decrease in the production of emissive species and an 18% increase in total heat production.