Modelling of two phase flows

Gas-liquid flow in vertical tubes is a flow pattern commonly found in many practical applications. It occurs in civil engineering applications and process equipment, e.g. in two- phase oil and gas pipelines, particularly in risers from subsea wells to platforms, as well as in oil, gas and geothermal wells, drain pipes for buildings. When gas-liquid mixtures flow in a tube, two phases distribute in a number of ways which characterize the spatial distribution of liquid and gas within the conduit. These are called flow patterns. Four dominant patterns in vertical pipes are suggested; bubbly, slug, churn and annular flows for upward flows. However there is only emprical knowledge existing in the literature for partical free surface downward flows. The objective of this work was to develop a physically-based hydrodynamic model for downward flows in vertical pipes and obtain experimental data by which the model could be evaluated. The results should permit the evaluation of the pressure and velocity distribution and volume fraction for gas-liquid flow through vertical pipes.