Experimental study on atomization characteristics of gas/liquid coaxial swirling nozzle in pressurized space

The atomization characteristics of a gas/liquid coaxial swirling nozzle in pressurized space were investigated. Under different background pressures, the Sauter mean diameter (SMD) affected by the background pressure, the relative velocity of atomization gas to oil and the oil velocity were studied through measuring the size distribution of the droplets with 70 mm to the exit orifice by Phase Doppler Particle analyzer (PDPA). The results show that when the relative velocity of atomization air to oil and oil velocity are fixed, SMD decreases as the background pressure increases; when the background pressure and oil velocity are fixed, SMD decreases as the relative velocity of atomization air to oil increases; under the condition of fixed atomization air pressure and background pressure, the affection rule of the oil velocity on the SMD has an inflexion. SMD increases firstly and decreases lately as oil velocity rises. Based on the experiments, the inflexion value is 9.91 m/s. Correlations between SMD and background pressure, relative velocity of atomization air to oil and oil velocity were analyzed according to the examination data.