Study on Spray Characteristics of Simulant Gel in Pressure Swirl Injector

In this study, the effect of gellant concentration on spray characteristics was investigated in a pressure swirl injector. The cold-flow tests of simulant gel were carried out to identify the air core formation of non-Newtonian fluid within the injector. Morphological analysis of the spray shapes was performed with regards to the air core location. Results show that the spray patterns can be classified into four distinct shapes as reported earlier in the literature. However, the transiting border between spray patterns was somewhat unlike due to the different gellant type used in this study. By categorizing the breakup regimes with dimensionless numbers, critical curves dividing each breakup regions were proposed. Regarding the quantitative spray characteristics, whether the gellant concentration increased or the pressure drop decreased, the spray angle was reduced, while the breakup length was elongated. These facts were partly due to the increased momentum loss triggered by relatively high viscosity.