L51509 Two-Phase Flow in Horizontal and Inclined Pipes at Large Pipe Size and High Gas Density

Knowledge of flow regime, holdup and pressure drop is needed in order to design gas and oil pipelines confidently and to minimize construction and operating costs. Previous public studies of two-phase flow in inclined pipes have used small diameter pipes two inches in diameter or less, and have primarily used air and water as the working fluids at low pressure (near one atmosphere). Present design methods are based upon the results of these experiments. In most advanced analyses available today, the flow regime transition is governed by a Froude number, the balance between inertial and buoyancy forces.

The primary objective of the work has been to obtain experimental data to challenge the present two-phase flow analysis methods for large pipe size, high gas density, and pipe inclination. Present analysis and design methods for two-phase flow in pipelines are based on correlations of data from small pipes of order 2-inches diameter or less, for air-water flows at pressures near one atmosphere. To achieve this objective, Creare performed experiments in an existing test facility with a special test section assembled for this project. Pipe diameter and gas density are closer to prototypical oil and gas pipeline conditions than previous experiments reported in the literature. The key experimental results include flow regime observations, pressure drops, and holdup measurements. The instrumentation in the test facility allows detailed characteristics of the flow such as slug velocity, slug frequency, liquid film velocity, and slug length to be measured in the slug flow regime.