Effect of nozzle-exit conditions on the near-field characteristics of a transverse liquid jet in a subsonic uniform cross airflow

Abstract

Several tapered- and sharp-edge nozzles with different exit diameters were used to investigate their effect on the near-field characteristics of a liquid jet injected transversely into a subsonic uniform cross airflow including a jet’s structure, column trajectory, and its breakup length. The experimental results demonstrated that at a low range of jet velocity, the axial turbulence intensity of a liquid jet issuing from a sharp-edge nozzle is greater than that of a tapered-edge nozzle. This resulted in a more irregular surface of the liquid column injected from a sharp-edge nozzle. However, the presence of hydraulic flip in the case of a sharp-edge nozzle at high jet velocity caused a reduction in the axial turbulence intensity of the injected liquid jet which has a smoother surface. Prior to the occurrence of hydraulic flip, the column trajectory of a liquid jet issuing from a tapered-edge nozzle is similar to that of a sharp-edge nozzle. However, the jet issuing from the latter penetrates farther than the former under hydraulic flip conditions. The presence of hydraulic flip increases the breakup length of a liquid jet. Furthermore, the present experiments allowed estimating the discharge coefficient of each nozzle by comparing with the mathematical correlations developed in our previous studies for predicting the column trajectory and breakup length of a transverse liquid jet. This allowed extending the applicability of these correlations to account for the effect of nozzle’s exit conditions on the near-field characteristics of a transverse liquid jet.