Enhanced modeling for resolved morphologies in co-current stratified wavy pipe flows

Abstract

This paper presents the development and validation of a model for simulating stratified flows with wavy interfaces within the two-fluid framework. A key focus is the interfacial momentum transfer closure for large-scale interfaces (LSIs), which is critical for Euler–Euler multiphase flow simulations involving distinct phase morphologies. A systematic evaluation of existing momentum transfer models for resolved morphologies, including those by Strubelj & Tiselj, Marschall, and a blended approach, is conducted alongside the proposition of a new Modified Mixture Model (MMM) for LSIs. The numerical simulations are compared against experimental data from the literature, revealing the limitations of traditional closure models for wavy flows and the impact of limited volume fraction on interfacial momentum transfer and wave growth. A novel diffusive stabilization approach is proposed, removing the inconsistencies introduced by limited phase-volume fraction in the momentum transfer modeling. The MMM model demonstrates robustness across mesh refinements, effectively capturing wave dynamics, mean water height, pressure drop, and key wave characteristics. The study also highlights the importance of turbulence damping, which increases the velocity gradients at the interface, contributing to phase decoupling and facilitating wave growth. These findings establish the MMM model as a reasonable approach for simulating stratified wavy flows.