Investigation of atomization characteristics of a dual-swirl centrifugal nozzle in a combustor environment

Abstract This study investigates a fuel atomization device consisting of a dual-circuit centrifugal nozzle and a two-stage axial swirler. PLIF and Mie scattering techniques, supported by a dual-wavelength laser (266 nm for kerosene fluorescence, 532 nm for Mie scattering), were applied to analyze spray characteristics under varying air pressure drops and fuel supply pressures. The laser path was optimized using dual-wavelength combining optics (266 nm high-reflection/532 nm high-transmission filter) to eliminate 1,064 nm stray light, improving measurement accuracy. The detection system was enhanced with an ultraviolet lens and bandpass filters, increasing light-collection efficiency fourfold while reducing the depth of field. Key conclusions include: In swirl-assisted atomization, a continuous liquid sheet is a physical prerequisite for ordered spray formation. Beyond this threshold, swirl intensity and fuel pressure synergistically control atomization. Increasing airflow expands the cone angle. Under low-to-medium conditions, fluorescence intensity in the cone region increases and the cone sharpens. Higher fuel pressure reduces cone angle and increases droplet Sauter Mean Diameter (SMD), but improves spray spatial uniformity, favoring mixture ignition. PDPA calibration confirmed SMD retrieval errors within 2.2 %–5.2 %.