A Multi-Species Enskog-Vlasov Solver to Determine Evaporation Coefficients of Fluids in High Pressure Environments

TL;DR

This paper presents a new multi-species Enskog-Vlasov solver that accurately predicts evaporation coefficients of fluids under high-pressure conditions, improving modeling for combustion and multi-phase fluid dynamics.

Contribution

The novel multi-species Enskog-Vlasov solver incorporates species-specific collision handling and a new pair correlation function, advancing high-pressure evaporation modeling accuracy.

Findings

Close match with molecular dynamics data for binary fluid relaxation

High accuracy in predicting liquid-vapor equilibria and evaporation coefficients

Significant improvements over traditional single-species methods

Abstract

This paper introduces a novel multi-species Enskog-Vlasov solver. It is used to determine evaporation coefficients of fluids under high-pressure conditions, a critical factor for efficient fuel mixing in internal combustion engines. The solver handles collisions for different fluid species separately, thereby accurately capturing species-specific interactions essential for realistic evaporation modeling. A new pair correlation function based on the BMCSL equation of state is employed to enhance modeling accuracy, though compliance with Onsager relations remains to be explored. Validation through various numerical simulations demonstrates the solver's capability. Results from binary fluid relaxation simulations closely match molecular dynamics (MD) data, highlighting accurate collision frequency modeling. Comparative studies against state-of-the-art models verify the solver's precision in predicting liquid-vapor equilibria and evaporation coefficients across diverse pressure scenarios. Detailed simulations of argon-neon mixtures with realistic particle diameters and masses underscore the significant improvements achieved by employing this multi-species approach over traditional single-species methods. Comparisons with the SAFT-VRQ Mie and classical density functional theory confirm the solver's reliability in predicting liquid and vapor compositions and detailed density profiles at interfaces over a wide range of pressures and temperatures. Further analyses illustrate complex dependencies of evaporation and condensation coefficients on temperature and pressure, consistent with existing research findings. Overall, this work advances computational modeling of multi-species evaporation processes in high-pressure environments at different temperatures, providing essential data for improved combustion modeling and broader applications in multi-phase fluid dynamics.