Measuring air core characteristics of a pressure-swirl atomizer via a transparent acrylic nozzle at various Reynolds numbers

• Published in: Experimental thermal and fluid science Vol. 34; no. 8; pp. 1475 - 1483
• Main Authors: Lee, Eun J., Oh, Sang Youp, Kim, Ho Y., James, Scott C., Yoon, Sam S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.11.2010; Elsevier
• Subjects: ADVANCED PROPULSION SYSTEMS; Aerodynamics; AIR; Air core; AIRCRAFT; Applied sciences; ATOMIZATION; Atomizers; DIESEL FUELS; Energy; Energy. Thermal use of fuels; ENGINEERING; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fluid dynamics; Fluid flow; FUEL INJECTION SYSTEMS; Fuel injector performance; Fuels; Injectors; INTERNAL COMBUSTION ENGINES; KEROSENE; LENGTH; NONLINEAR PROBLEMS; NOZZLES; RESIDUAL FUELS; REYNOLDS NUMBER; SPRAYS; STABILITY; Swirl spray; TEMPERATURE DEPENDENCE; Temperature effect; TEMPERATURE RANGE 0273-0400 K; VISCOSITY; Temperature effect; Air core; Swirl spray; Fuel injector performance; Motor fuel injection; Test facility; Internal combustion engine; Nebulizor; Experimental study; Performance; Pulverized fuel; Liquid spraying
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2010.07.010

Because of thermal fluid-property dependence, atomization stability (or flow regime) can change even at fixed operating conditions when subject to temperature change. Particularly at low temperatures, fuel’s high viscosity can prevent a pressure-swirl (or simplex) atomizer from sustaining a centrifugal-driven air core within the fuel injector. During disruption of the air core inside an injector, spray characteristics outside the nozzle reflect a highly unstable, nonlinear mode where air core length, Sauter mean diameter (SMD), cone angle, and discharge coefficient variability. To better understand injector performance, these characteristics of the pressure-swirl atomizer were experimentally investigated and data were correlated to Reynolds numbers ( Re). Using a transparent acrylic nozzle, the air core length, SMD, cone angle, and discharge coefficient are observed as a function of Re. The critical Reynolds numbers that distinguish the transition from unstable mode to transitional mode and eventually to a stable mode are reported. The working fluids are diesel and a kerosene-based fuel, referred to as bunker-A.