Expansion and contraction of an air‐water mixture in vertical flow

Abstract

Abstract An experimental two‐phase flow study was made on an air‐water system at atmospheric pressure to obtain information on the effect of expansion and contraction of flow area on the relative velocity of the two phases. The data show that the relative velocity and hence the mean void fraction of the air‐water mixture changed following either an expansion or contraction; however the magnitude of the change was not great and could be predicted by a semitheoretical equation. The air‐water data are also compared with data taken from a steam‐water system at 150 to 600 lb./sq. in. In addition, a photographic study was made of the transition zone, and phase distributions were obtained by the use of a radiation attenuation traversing technique.