Three types of atomizers, prefilming flat sheet, plain jet and pressure swirl have been tested upon their suitability for premixing ducts of lean premixed prevaporized combustors for gas turbines. Their Sauter Mean Diameters, particle size distribution widths and penetration depths have been studied for variations in gas velocity, gas pressure, fuel flow rate and atomizer scale. Tests were carried out in a pressure vessel at gas densities and velocities prevailing in real premixing ducts for cruiseflight conditions.
Atomizer design and fuel flow rate affect the fuel distribution and therefore the fuel concentration near the point of atomization, which leads to differences in the mean drop diameter and mainly the width of the dropsize distribution of the spray. The mean drop size is dominated by the velocity of the air relative to the liquid and, within the investigated range, depends only weakly on the air density.