The effect of boiling-up on the shape and droplet size of a jet of superheated water discharged through a semi-cylindrical nozzle

Abstract

An experimental investigation of the dynamics of boiling-up of a jet of superheated water discharged from a high-pressure chamber through a short semi-cylindrical nozzle has been conducted. Changes in the jet shape have been traced under changes in the thermodynamic parameters (temperature Ts, pressure ps) corresponding to the phase equilibrium line in a wide range Ts = 380–580 K, ps = 0.1–10 MPa. A complete jet opening has been revealed, and the temperature boundaries at which this shape of the jet manifests itself have been established. The loss of stability of the jet shape has been revealed in passing both from the conical form to the complete opening and back. The droplet size of a boiling-up jet has been determined by the microscopic method. The paper presents data on the particle size distribution in a flow at different boiling-up regimes. The dependence relating the particles mean diameter in a superheated liquid to variations in its pressure on the line of liquid – vapor phase equilibrium has been obtained.