A study on burning behavior of rich premixed-spray jets with different fuel volatilities

Burning behavior of fuel-rich premixed spray was experimentally studied with different fuel volatilities. Overall equivalence ratio of spray jet φ_sj was quite larger than unity to establish a rich premixed-spray combustion. N-octane, ndecane, and n-tridecane were used as a liquid fuel. With φ_sjfixed to 12 and with almost the same atomization condition (about 100 μm in Sauter mean droplet diameters d ₃₂), burning behavior depended on the fuel type. An internal flame was observed for n-tridecane but did not appear for n-octane and ndecane. Flame height also depended on the fuel type. The flame height of n-octane was the largest among these three fuels under any atomization condition. When φ_sjand atomization condition were varied, an internal flame appeared for some conditions of φ_sjand atomization condition even for n-octane and n-decane. The transition of combustion modes with and without the internal flame was discussed based on fuel volatility.