On the assessment, implementation, validation, and verification of drag and lift forces in gas–liquid applications for the CFD codes FLUENT and CFX

The understanding of two-phase gas–liquid flows is of utmost importance in a large range of industrial applications, including the petrochemical, pharmaceutical, biochemical, nuclear, and metallurgical industries. At ANSYS, significant effort is being made in assessing the physical force models present in both FLUENT and CFX. This includes the investigation of the interfacial closures (drag, lift, wall lubrication, turbulent dispersion, and virtual mass), heat and mass transfer, cavitation, wall boiling, population balance approaches, bubble breakup and coalescence, and turbulence modeling. This assessment is being done with the objective to conduct an audit/validation of the current models, features, and capabilities, as well as the identification and closing of gaps and differences between CFX and FLUENT. The work presented here is mostly focused on the assessment, implementation, and validation of the drag and lift interfacial closures. The numerical assessment and validation are performed using both analytical and industrial-like test cases for complex bubbly flows (both with wall and bulk void fraction maximums), as well as transitional flow from bubbly to slug regime using the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) experimental facility known as MT-Loop.