Computational fluid dynamics (CFD) study of bubble carry-under in gas-liquid cylindrical cyclone separators

The gas-liquid cylindrical cyclone (GLCC((C))) separator is an attractive compact separator alternative to the conventional vessel-type separator. Thus, it is important to develop predictive tools for design and to be able to improve the technology of the GLCC. Previous studies on the GLCC have focused on mechanistic models capable of predicting the operational envelope for liquid carryover and on the understanding of the flow field in the GLCC. The main objective of this work was to investigate the behavior of small gas bubbles in the lower part of the GLCC, below the inlet, and the related gas carry-under phenomena. This investigation was performed by flow visualization and by using a commercially available computational fluid dynamics (CFD) code. Simulations of single-phase and two-phase flows were carried out and bubble trajectories were obtained in an axisymmetric geometry that represents the GLCC configuration Bubble trajectory analysis was used to quantify the effects of the important parameters on bubble carry-under. These include bubble size, ratio of the GLCC length below the inlet to diameter, viscosity, Reynolds number, and inlet tangential velocity.