Two-Phase Flow Patterns and Pressure Drop Inside a Vertical Pipe Containing a Short Helical Tape Insert

Swirling gas-liquid two-phase flow patterns and pressure drop in vertical pipes of a large diameter are widely present in practical applications but not well documented in experimental studies. This paper presented an experimental study on gas-liquid two phase flow patterns and pressure drop inside a vertical pipe of 62mm in inner diameter (ID) containing a helical tape insert. Experimental results were obtained in a vertical visualization test section with a length of 7m, liquid mass velocities ranging from 0.3 to 1000 kg/(m²·s), and gas mass velocities from 3.2 to 900kg/(m²·s). Considering the decay of the swirl flow, the swirling flow regime map at different cross sections (z/D = 16, 32 and 64) were concluded, and their effects on the pressure drop were investigated.