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 C_α 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.