The present work aims to provide an explanation to the phenomenon of breakdown of the thin liquid film created by impinging two-phase, liquid–gas jet. Existing in the literature models describe merely the breakdown of single phase liquid films. The model presented here is based on examination of mass and energy equations under the applied criterion of the minimum of total energy. That allows to determine the minimum thickness of isothermal, thin liquid film created by impinging two-phase jet on a solid surface. The mechanical energy of the system consists of kinetic energy of liquid film and surface energy of all physical surfaces consisting for the control surface. An analytical expression for the minimum thickness of such liquid film is derived. The liquid film thickness at the breakdown is a function of the contact angle and shear stresses on the liquid–gas interface. Some comparisons with the experimental data are shown exhibiting a good performance of the postulated model.
Przedstawiono analize teoretyczną i badania eksperymentalne zjawiska rozrywania sie warstwy cieczy powstalej na powierzchni ciala stalego z uderzającej strugi.
The paper is concerned with the hydraulic jump formed by an axisymmetrical aerosol jet, impinging upon a flat plate. The experiments carried out yield that liquid layer formed by an aerosol impinging jet experiences a hydraulic jump at more far downstream location, comparing with the same layer configured by a single-phase impinging jet. This means that an aerosol jet forms a far larger area, providing high heat -transfer rates.
An experimental investigation of a thin water film driven by steam, its evaporation and breakdown, was carried out. The shear stresses, the main factor influencing the film motion, were calculated as a function of the “blowing parameter”. The influence of the blowing parameter on evaporation and breakdown of the film was investigated. The results obtained are in agreement with a theoretical analysis which included the effects of the evaporating mass stream and of small droplets within the vapor boundary layer.
