Coupled Modeling of CO_(2) Frosting,Fluid Flow,and Heat Transfer under Cryogenic Conditions Using a Nucleation-Based CFD FrameworkOA

A two-dimensional Computational Fluid Dynamics(CFD)model,grounded in classical nucleation theory,is developed to investigate CO_(2) frosting and the associated heat transfer under cryogenic conditions.The model integrates gas–solid phase-change kinetics with multiphysics transport equations to capture the coupled phenomena governing frost formation.The Peng–Robinson equation of state is employed to predict CO_(2) frost points in binary mixtures,with model predictions validated against experimental data,yielding errors in frost thickness and thermal conductivity below 15%.The results demonstrate that decreasing the cryogenic wall temperature from 160 K to 150 K increases the average frost thickness and density by 57% and 78%,respectively,while advancing the peak in thermal resistance by approximately 5 min.A reduction in CO_(2) mol fraction from 10% to 6% leads to an 82% decrease in average frost density.Although inlet velocity exerts a limited influence on frost density,excessively high velocities increase porosity and inhibit densification.Flow field analysis reveals that progressive frost growth constricts the effective channel area,resulting in a local velocity increase of approximately 23%.Moreover,the spatial distributions of supersaturation and nucleation rate exhibit strong consistency.These findings elucidate the complex coupling between CO_(2) frosting,fluid flow,and heat transfer in Pressurized Liquefied Natural Gas(PLNG)systems,offering theoretical insights for optimizing low-energy CO_(2) cryogenic capture and enhancing natural gas liquefaction processes.