Slug Frequency in High Viscosity Liquid and Gas Flow in Horizontal Pipes

Slug flow is one of the commonly encountered liquid and gas two-phase flow patterns. The accurate prediction of its behaviours is crucial for practical engineering applications. Liquid viscosity and pipe diameter are found to have significant impacts on slug frequency, but available data for high viscosity liquid which has a viscosity above 1.0 Pa s might be still scarce. In the present work, slug frequency in high viscosity liquid and gas slug flows is studied. Experiments are performed in 0.026 m ID and 0.074 m ID horizontal pipes with a liquid viscosity range of 1.0 Pa s to 7.5 Pa s. Results are discussed in terms of viscosity and diameter effects, and compared with existing models. A new correlation is proposed to predict slug frequency for high viscosity liquid and gas flows.