Investigation and comparison of spray characteristics of pressure-swirl atomizers for a small-sized aircraft turbine engine

Abstract

The quality of liquid fuel atomization highly affects the formation of gaseous pollutants and particulate matter emissions from combustion processes. Spray characteristics of two geometrically different pressure-swirl atom-izers for a turbojet engine in light aircraft were measured on a cold test bench. A spill-return atomizer and its intended replacement simplex atomizer were investigated using Particle Image Velocimetry (PIV) and Phase-Doppler Anemometry (PDA). Single-camera and stereoscopic PIV measurements yielded velocity distributions in the axial cross-section of the spray cone. PDA measurements provided dropsize distribution and axial velocity data. Acquired results reveal significant differences in spray characteristics of the nozzles investigated at the same fuel injection pressures. The simplex nozzle produced spray with Sauter mean diameters lower by 5–20 um depending on the regime, its spray was more stable but its shape greatly varied with fuel injection pressure. These differences are discussed in detail, their analysis indicate a potential for spray improvement provided by the novel atomizer design and elucidates the possible impact of the nozzle replacement on the combustion process.The quality of liquid fuel atomization highly affects the formation of gaseous pollutants and particulate matter emissions from combustion processes. Spray characteristics of two geometrically different pressure-swirl atom-izers for a turbojet engine in light aircraft were measured on a cold test bench. A spill-return atomizer and its intended replacement simplex atomizer were investigated using Particle Image Velocimetry (PIV) and Phase-Doppler Anemometry (PDA). Single-camera and stereoscopic PIV measurements yielded velocity distributions in the axial cross-section of the spray cone. PDA measurements provided dropsize distribution and axial velocity data. Acquired results reveal significant differences in spray characteristics of the nozzles investigated at the same fuel injection pressures. The simplex nozzle produced spray with Sauter mean diameters lower by 5–20 um depending on the regime, its spray was more stable but its shape greatly varied with fuel injection pressure. These differences are discussed in detail, their analysis indicate a potential for spray improvement provided by the novel atomizer design and elucidates the possible impact of the nozzle replacement on the combustion process.