CFD analysis of two-phase cross-flows in the Rowe and Angle experiment

This study validates NEPTUNE_CFD against Rowe and Angle’s 1967 two channel cross-flow experiments over six series that span outlet pressures ∼ 61 - 64 bar , homogeneous inlet mass flux G ≃ 1 . 3 - 4 . 1 × 1 0 3 kgm − 2 s − 1 , and average outlet qualities x ̄ out ∈ [ − 0 . 35 , 0 . 33 ] . The solver employs an Eulerian two-fluid URANS framework with SSG Reynolds-stress turbulence and conjugate heat transfer. Sub-cooled sets are modelled with a dispersed-bubbly formulation (Ishii-Zuber drag, Tomiyama lift, turbulent dispersion, Ruyer–Seiler interfacial area transport equation); near-saturated sets use NEPTUNE_CFD GLIM model to blend dispersed and large-interface closures. For sub-cooled series, NEPTUNE_CFD reproduces the outlet mass-flux split and incremental enthalpy in all series (a small bias is present at the lowest G ). For near-saturated series, the GLIM multi-regime model implemented in NEPTUNE_CFD enables a consistent representation of multiple flow conditions and yields good agreement with experimental trends across three regimes: single-channel boiling, partial re-mixing at boiling onset in the colder channel, and high-void-fraction redistribution with persistent phase separation. Predicted outlet enthalpies lie within experimental uncertainty for subcooled sets (direct thermocouple measurements), while they are slightly overestimated in the hot channel of saturated series, where data are reconstructed from downstream thermal balances and thus less reliable. Mixing rates and void patterns match the inferred physics. The analysis identifies turbulent dispersion in bubbly regime, and large-interface normal friction as high-leverage closures. Within the explored range, NEPTUNE_CFD yields quantitatively reliable two-phase cross-flow mixing and a robust CFD database that will be used for up-scaling of diffusion/dispersion models to CATHARE3-3D. • NEPTUNE_CFD validated against Rowe & Angle cross-flow tests at 60 bar. • Accurate energy & mass redistribution from subcooled to high-void regimes. • NEPTUNE_CFD GLIM consistently models transitions up to churn & annular flow. • Turbulent dispersion & large-interface friction are high-leverage closures. • Reliable CFD database built for upscaling to system & porous media codes.