Two-Phase Flow Across Small Sudden Expansions and Contractions

Two-phase flow approaching singularities such as abrupt expansions and sudden contractions is widely encountered in typical industrial and heat exchanging devices. There have been some studies concerning this subject but they mostly are applicable for larger channels. In this study, the first attempt is made to review the existing efforts concerning two-phase flow across sudden expansions/contractions and to examine the applicability of the existing correlations with respect to the recent data in small channels. The second part of this study presents some newly measured pressure drops and observed flow patterns pertaining to some special flow phenomena by expansion/contraction. For an abrupt expansion, it is found that the existing correlations all fail to provide a reasonably predictive capability against the newly collected data. Furthermore, a unique flow pattern called “liquid jet-like flow pattern” occurs at a very low quality region of total mass flux of 100 kg · m−2· s−1, and it raises a setback ph...