ID 95

Investigation of Spray-Induced Air Flow of Dual-Plume Flash-Boiling Spray

 

Abstract:

Two-phase interaction between ambient air and fuel spray takes place during and after the spray injection. The fuel spray exchanges its momentum to its surrounding air to induce air flow motion. Air entrainment and recirculation exhibit during injection, while wake air flow is formed after the end of injection. The interaction between fuel droplets and ambient air is responsible for this spray-induced flow. Flash-boiling spray taking place under high superheat degree generates tremendous number of fine droplets which might be easier to transfer their momentum to the air. Moreover, multi-hole injector spray is found to collapse under flash-boiling condition, resulting in a deformed spray geometry which could potentially affect the induced air flow. Therefore, this research focuses on characterization of this spray-induced flow under superheated fuel conditions. A dual-plume spray generated by a custom-made two-hole injector is utilized to investigate the inter-plume region where the collapse first happens. The velocity distribution between adjacent plumes under various fuel superheat degree are spatially and temporally resolved. It is found that the collapse effect is caused by the fuel attachment of the two individual plumes near the injector nozzle. Furthermore, the air in the inter-plume region is pushed downstream under superheated condition which is in the opposite direction when the spray is under subcooled condition.