Understanding ice crystal melting in an icing wind tunnel through two-way coupled CFD simulation

Ice crystal icing poses a significant threat to aircraft engine safety. The sticking potential of ice crystals is mainly determined by ice melting behavior, but the coupled behavior of ice melting, turbulent dispersion, and the gas flow remains insufficiently understood. This study develops a new two-way coupled Eulerian–Lagrangian solver integrated into OpenFOAM to simulate the transport and melting behavior of ice crystals. The three-stage phase-change model is employed to capture particle melting, while turbulent dispersion is represented using the discrete random walk model. A parametric study is conducted to investigate the effects of flow conditions and particle properties on melting behavior in an icing wind tunnel. The solver is validated through code-to-code comparison and experimental data. The predicted variations in gas temperature and humidity due to two-way coupling align well with measurements, whereas the liquid water content is qualitatively consistent but overestimated. Increasing humidity, total temperature, pressure, and particle aspect ratio enhances melting potential, while higher Mach numbers and larger particle sizes reduce it. The influence of uncertainties in particle injection boundary conditions reported in the literature is also discussed.