Analysis of Soot Particulate Formation in a High-Pressure Confined Spray-Flame

The role of individual parameters in the formation and oxidation of soot particulates in spray combustion at elevated pressure, such as is found in the diesel engine is investigated. Variations of vapour-phase equivalence ration, flame temperature, soot concentration and mole fractions of local gas-phase species are predicted along the axis of a confined liquid-fuel spray flame, under steady conditions. A rise and fall in the soot concentration is predicted along the flame with the peak value increasing with local pressure and equivalence ratio.

Test results with diesel fuel using a high-pressure continuous liquid-fuel spray combustor, under conditions free from the cyclic variations encountered in a diesel engine are presented showing reasonable agreement with those predicted. Digitised micrograph images of soot agglomerates with particle-size analysis are presented.