Numerical Study of Void Fraction Distribution in Horizontal Bubbly Flow Using a Euler–Euler Two-Fluid Model

Gas–liquid bubbly flow in horizontal pipes is widely encountered in energy and process systems, where accurate prediction of phase distribution is essential for safety and performance assessment. In Euler–Euler two-fluid simulations, the predicted void fraction profile is highly sensitive to the choice of interphase force closures. In this study, the effects of drag, lift, wall lubrication, and turbulent dispersion forces on the void fraction distribution in horizontal bubbly flow are numerically investigated using a Euler–Euler two-fluid model. Simulations are performed for three experimental cases covering a wide range of bubble Reynolds numbers (Reb = 55, 140, 6283), and the predicted void fraction profiles are compared with available experimental data. The results indicate that the void fraction profile is insensitive to drag force model selection. In contrast, the lift force plays a dominant role in controlling the lateral migration of bubbles and the formation of the upper-wall void fraction peak. The wall lubrication force significantly influences the near-wall phase distribution, with different models exhibiting varying levels of agreement with the experimental data at different bubble Reynolds numbers. Turbulent dispersion is found to be essential under horizontal conditions, and the Lopez-de-Bertodano model is robust for all cases. The present results provide insight into the relative roles of different interphase forces in shaping the phase distribution in horizontal bubbly flow.