The flow in the header of a finger-type slug catcher is analyzed using CFD techniques. In order to design a high-performance finger-type slug catcher, it is necessary that the fluid flow in the inlet header manifold is evenly distributed among the different fingers.
A detailed flow analysis by means of Computational Fluid Dynamics using the proven OpenFOAM® code is performed. Different configurations are defined and compared using the time-averaged mass flow at the finger inlets. At the inlet, the flow velocity is specified, while the gradient of the pressure is set to zero. Furthermore, at the symmetry plane, the flow velocity perpendicular to this plane is set to zero, no flow is possible through this plane. Additionally, the relative pressure at the outlet boundaries is set to zero, such that the flow velocity will be calculated accordingly. The time-averaged mass flow at the finger outlets is calculated by a multiplication of the gas density and the volume flux through these boundaries.
The mass flow at the finger inlets is highly mis-distributed in the original design configuration. Backflow almost occurs at certain fingers. A design modification where the inlet header manifold has an increased and constant diameter improves the mass flow distribution significantly.
The mass flow distribution in the inlet header manifold is further improved by applying a split in the main header pipe.