Fuel spray burning regime and initial conditions

The structures of air blast atomized heavy fuel oil spray flames, in particular, the mechanisms of droplet burning, are examined as functions of initial conditions by using a novel atomizer design. A particle sizing instrument and a spray momentum measurement device are used to calibrate this atomizer so that parametric variations can be made of the initial droplet size distribution, spray momentum, fuel flow rate, and air/fuel ratio. Information is obtained on flame length, droplet burning regime (individual or group combustion of droplets), and combustion chamber wall temperature as a function of initial conditions. Supported by this information, reasoning regarding the physics of the flows is used to propose that the relative values of two parameters, which incorporate initial spray momentum, droplet size distribution, and fuel flow rate, can give a good indication of the likely burning regime and other important features of spray flames.