Prediction of Optimum Length to Diameter Ratio for Two-Phase Fluid Flow Development in Vertical Pipes

We investigate, via numerical simulation technique, the effect of length-to-diameter ratio on transient air-water two-phase flow in vertically upward cylindrical pipe geometry for parameterisation of the pilot scale laboratory multiphase flow rig. Variables such as axial velocity along the leading Taylor bubble, Taylor bubble length and Taylor bubble velocity are considered. A hydrodynamic entrance length required to establish a fully developed two phase flow was critically evaluated. Aperiodic behaviour on time and space dictates the complexity of continuous and unstable gas liquid flow. The porous injection configuration produced small bubble sizes compared to a single gas injection configuration even at higher gas injection rates.