Simulation of the vane-type bubble separator using a hybrid Euler–Euler/volume-of-fluid approach

The vane-type bubble separator is a critical component in the fission gas removal system of molten salt reactors, requiring accurate simulation of its two-phase flow field characteristics. To overcome the limitations inherent in traditional Euler–Euler and volume-of-fluid methods, this study adopts a hybrid methodology integrating both approaches. This strategy effectively addresses flow pattern transitions from dispersed to segregated flow while enhancing interfacial resolution. Comparative analyses of varying Cα values were conducted to evaluate multiphase model performance. Large-eddy simulation was concurrently implemented to resolve turbulent flow features. Results demonstrate that the hybrid method, through incorporation of volume fraction transport equations, achieves superior gas–liquid interface definition. Numerical phase distribution predictions show strong agreement with experimental observations, successfully reproducing transitional flow patterns. Subsequent flow field analysis utilizing Q-criterion revealed distinct vortex structures, with tangential velocity profiles conforming to Rankine vortex patterns and identifiable reverse axial flow regions. A stable symmetrical gas core was consistently maintained within the swirl chamber. This methodology establishes a validated framework for simulating gas–liquid separation processes.