Sprays formed by flashing liquid jets

Abstract Liquids forced from a high‐pressure zone into a low‐pressure zone often cross the equilibrium pressure for the liquid temperature and disintegrate into a spray by partial evolution of vapor. The ordinary aerosol dispenser is a common example of this operation, and flash boiling is another. This paper reports on a study of the sprays formed by such a process and of the mechanism of spray formation. Sprays from water and Freon‐11 jets were analyzed for drop sizes, drop velocities, and spray patterns. The breakup mechanism was analyzed and data presented to show some of the controlling factors. A critical superheat was found, above which the jet of liquid is shattered by rapid bubble growth within it. The bubble‐growth rate was correlated with the Weber number, and a critical value of the Weber number was found to be 12.5 for low‐viscosity liquids. The mean drop size was also correlated with Weber number and degree of superheat. The spray from rough orifices and sharp‐edged orifices was compared with sprays produced from cold liquids by other techniques and was found to be comparable in all respects except temperature.