Turbulent jet breakup : theory and data

Understanding the breakup of turbulent liquid jets is important for many applications including spray combustion, fire suppression, and water jet cutting. Turbulent jet breakup models are rarely fully predictive, and typically require re-calibration to experimental data for different cases. In this work the existing models for turbulent jet breakup are reviewed, highlighting the successes and shortcomings of existing and new approaches. A critical shortcoming of most existing models is the neglect of a measure of the strength of the turbulence like the turbulence intensity. New models are developed to address this shortcoming and others. Existing and new models are compared against a large experimental compilation, primarily from the archival literature. Because the physical mechanisms causing breakup can vary, a new regime diagram was developed in this work, allowing the breakup regime and consequently how to model a particular jet to be determined. Problems common in the validation of turbulent jet breakup models are detailed. A model for the turbulence intensity at the outlet of a nozzle is developed. Finally, a theoretical model is developed and validated for the range of a large firefighting water jet including the effects of jet breakup and air entrainment