Flow pattern transition for vertical downward two-phase flow in capillary tubes. Inlet mixing effects

Experimental results of flow pattern for vertical downward two-phase flow in capillary tubes are reported and flow pattern regime maps are presented. In addition theoretically based transition criteria for the flow pattern are presented. The experimental results and theory seem to match each other fairly well. When results given in this paper are compared with empirical ones presented in literature stratified flow has not been reported in this study. Additional experiments were undertaken and inlet mixing effects have been found to be extremely important for the existence of fully developed flow.