THE APPLICATION OF THE LIGHT ABSORPTION TECHNIQUE TO CONTINUOUS FILM THICKNESS RECORDING IN ANNULAR TWO-PHASE FLOW

Abstract

An attempt was made to measure continuously the instantaneous thickness of the climbing film in vertical co current air/water flow by means of the absorption of a light beam in a dye added to the water. A single passage of the light through the film was arranged by bringing it up close to the inner surface of the film through an air-purged capillary tube which penetrated one wall and traversed most of the droplet-laden air core; after passage through the film and the transparent wall the light fell on a photovoltaic cell whose signal was amplified and displayed on an oscilloscope. Although this general method was reported as satisfactory with falling films, the sharp wave profiles and presence of spray in the climbing film regime of interest were found to introduce gross refraction and scattering effects which swamped other signals. The technique was abandoned. (auth)