Comparison of Spray Characteristics of a Simulant Gel in an Impinging Injector Using an Orifice with an Internal Groove

This study investigated the influence of a grooved orifice on the spray characteristics of a non-Newtonian fluid in an impinging injector. A simulant gel was used as the working fluid, and two orifice configurations (plain and grooved) were examined. The spray behavior was characterized in terms of the discharge coefficient (Cd), breakup length, spray angle, and spatial mass distribution. The discharge coefficients of the two orifices were found to be comparable; however, the grooved orifice resulted in a shorter breakup length and larger spray angles and spatial mass distributions than the plain orifice. These differences were attributed to the groove feature, which promoted more turbulent-like jet development and facilitated the formation of an unstable liquid sheet, thereby enhancing breakup. These results suggest that a grooved orifice could be an effective geometry for improving the spray performance of the simulant gel.