NUMERICAL INVESTIGATION OF DUCTED FUEL INJECTION WITH DIFFERENT DUCT SIZES

Ducted fuel injection is a newly established strategy that follows the idea of leaner lifted-flame combustion, aiming to enhance premixing and reduce soot. A better understanding of spray characteristics of the mixing process is of great significance so that this technology can be fully applied. Ducted spray with different duct sizes was studied through numerical simulation. Results showed that longer and narrower ducts led to higher spray velocity due to decreased total gas entrainment-lower gas resistance, and the restriction of radial development of the spray in the near field. Proper duct configuration improved spray atomization in terms of reducing droplet size. The analysis of a special appearance called a “mushroom-shaped” head was also performed. As the jet penetrates through the duct, shearing vortices formed and developed. Under the effect of the pressure difference between the duct inside and outside, the spray tip deformed and diffused radially.