Abstract
KEY WORDS - mass flow rate, superheated fuel sprays, superheat degree, fuel temperature, ambient pressure
ABSTRACT
Flash boiling spray has been demonstrated to produce better atomization even at low injection pressures. As this type of spray is usually generated by preheating the fuel within the injector to increase its superheat degree, the density and viscosity of fuel is also changed by the elevated temperature, which subsequently affects the flow rate of injection. While previous works about flash-boiling sprays mainly focused on their structure characteristics and formation mechanisms, flow rate of fuel under superheated conditions is rarely studied. Therefore, assessment into injected flow rate of flash boiling spray is necessary. In this study, the effects of temperature, ambient pressure and superheat degree on the injected flow rate were investigated under a wide range of superheated conditions. Together with the previous studies of flash-boiling sprays and superheated flow inside an optical nozzle, the behavior of injection flow rate was illustrated. Under non-superheated conditions, the flow rate keeps unchanged. Under superheated conditions the flow rate and equivalent cross-sectional area of flow decreases with increasing superheat degree and increasing temperature. Within the studied range, the decrease of mass flow rate and equivalent cross-sectional area of flow is less than 12% and 9%, which will not cause problems in engineering applications.