Estudo numérico e experimental do escoamento bifásico líquido-gás em célula de balanço

Abstract

The oil and gas industry faces several problems in the extraction and production of oil, and to carry out studies that assist in solving these problems, long piping circuits are often used. These studies are often costly and require large facilities to be set up and conducted. Part of these studies has been carried out in rocking cells, which have emerged as an alternative in relation to pumped flows, which may have reduced dimensions, contain high pressures and have better temperature control in an economically viable way. However, as far as the author is aware, there are still few studies that describe the hydrodynamic behavior of the flow within the rocking cells. This work presents a numerical study (implemented in the open software OpenFOAM using the multiphase model VOF) and experimental (developed exclusively for the validation of the numerical model) of a two-phase air-water flow inside a 1.2m long rocking cell and 51.8 mm internal diameter. The cell, in question, allows changing three main factors that generate the movement of fluids: oscillation frequency, fill ratio and maximum angle of inclination. In this study we used three oscillation frequencies defined by valleys predetermined by the equipment: 0.925rad / s, 1.24rad / s and 1.55rad / s. The filling ratio was varied from 10% to 90% and the maximum angulation of the cell was fixed at 17.5 °, an angle that brought well-defined phase movements. The numerical simulations were satisfactorily validated with experiments. The reproduced cases presented flows with stratified and slug flow characteristics. The analysis were performed in the center of the tube. Fluid flow rates in the study area were found to be the same between the phases, only with different directions, reaching velocities of up to 2.5 m/s. The numerical model developed and validated here can be used as a study tool to assist in the understanding of real phenomena that involve two-phase flows in rocking cells.