A new set of measurements of pressure drops and liquid hold-up taken at TEASistemi Laboratory under conditions of stratified gas-liquid flow has been used to improve the closure relations adopted in MAST, a new transient one-dimensional multiphase flow simulator. These data are relative to water-nitrogen flow in a 3.15 in (80 mm) horizontal pipe operating at pressures in the range 72.5-362.6 psig (5-25 bar). The results obtained allowed a more reliable description of stratified gas-liquid flow in hydrocarbon transportation pipelines. A comparison with the performance of other flow simulators is also presented.
The simulation of gas-liquid flow in pipelines can be based on the solution of 1-D mass, momentum and energy conservation equations, . These equations depend on a set of closure relations, in general of empirical nature. The closures adopted in commercial codes are similar to those proposed in the open literature, on the basis of data taken at atmospheric pressure, in small diameter pipes. These correlations have then been modified on the basis of experimental data taken at conditions which more closely resemble field conditions. Field data are used for the final validation of these codes. Notwithstanding the amount of work performed for code testing and validation, quite often the simulation of real pipelines remains unsatisfactory, the reason probably being that from one hand the quality of available data is poor, from the other, these data are quite limited and do not cover the full range of flow parameters encountered in practical applications. In the present work, we use different data sets relative to stratified gas-liquid flow in horizontal pipes to test major commercial codes used for pipeline flow simulation. Among these data we include a new set of measurements of pressure drops and liquid hold-up taken at TEASistemi Laboratory.