Laminar dispersion force effects on two-fluid modelling and simulation of bubble column hydrodynamics

The two-fluid model (TFM) is foundational for modelling and simulation of dispersed-regime multiphase flows which are pervasive in natural and industrial processes. The TFM provides a coarse-grained representation of complex multiphase flows without explicitly capturing interfaces between phases through the use of volume-, time-, or ensemble-averaging. This results in the benefit of significantly reduced computational complexity but at the cost of increased approximation requiring accurate interphase transfer closures, compared to interface-capturing models. The choice of interphase transfer closures for TFM accuracy has been one of the main foci of past research, which is expansive due to the various multiphase system combinations (e.g. gas dispersed in liquid and liquid dispersed in gas). Recent research using detailed interface-capturing models has shown that the inclusion of a laminar dispersion force in the TFM when modelling bubbly flows both improves physical fidelity and mathematical completeness. In this work, a simulation-based study is performed to determine the effects of including different recently proposed laminar dispersion force models on both numerical stability and physical fidelity of a TFM formulation for gas dispersed in liquid multiphase flows. It includes a formulation of a TFM based on Brennen’s canonical formulation incorporating various recently developed laminar dispersion force closures. Overall, it is shown that inclusion of a laminar dispersion force both improves numerical stability and physical fidelity through validation with past experimental results.