Study on hydrodynamic slug flow mitigation with wavy pipe using a 3D–1D coupling approach

• 3D–1D coupling models of wavy-pipe systems experiencing hydrodynamic slug flows were developed.
• The flow behaviour in wavy-pipe systems was characterised through STAR–OLGA coupling models.
• The upstream slug degenerates into a ‘liquid dense zone’ of a reduced density downstream of wavy pipe.
• A wavy pipe with excessively higher amplitude is even less effective on mitigating slug flows.
• A wavy pipe with the same amplitude but a greater length, i.e. more bends, is more effective.

Objective: A wavy pipe, constructed by connecting standard piping bends in series in one plane, was proposed to mitigate hydrodynamic slug flows in horizontal pipelines.Methods: A newly developed 3D–1D co-simulation method, i.e. STAR–OLGA coupling, was applied to model the wavy-pipe systems experiencing hydrodynamic slug flows. The flow characteristics of slug flow in the wavy-pipe systems were investigated, through which the effectiveness of the wavy pipe on slug mitigation and how the geometrical parameters of the wavy pipe affecting its performance were examined.Results: It has been found that the upstream liquid slug degenerates into a ‘liquid dense zone’ of a greater length downstream of the wavy pipe due to the gas penetration into the slug body. A reduction of the effective density of the ‘liquid dense zone’ from that of the upstream slug body is resultant showing the effectiveness of the wavy pipe on mitigating the adverse impacts of slug flow. The amount of gas penetration increases then decreases with the increasing wavy-pipe amplitude indicating that excessively higher amplitude is even less effective on introducing the gas phase into the slug body. Differently a wavy pipe with the same amplitude but a greater length, i.e. more bends, is more effective.Conclusions: It is concluded that the wavy pipe works by reducing the effective density of the liquid slug through introducing the gas phase into the slug body in the push-out process in each bend of the wavy pipe and the geometrical parameters need to be designed properly in specific applications.