In order to determine spray droplet size in a diesel engine, fuel was injected into high-pressure, room-temperature gaseous environments with a diesel engine injection system. Droplet size was measured using the liquid immersion sampling technique with a mixture of water-methylcellulose solution and ethanol used as an immersion liquid for diesel fuel oil.
The volume distribution of diesel spray droplets is well correlated with chi square distribution with freedom, ϕ = 8, in the range of this investigation.
The Sauter mean diameter increased with increasing back pressure, with the amount of fuel in a spray, and with decrease in pump speed. An empirical correlation was developed between effective injection pressure, air density, the quantity of the fuel delivery, and the Sauter mean diameter of spray droplets.