A new FCCS-CFD coupled method for understanding the influence of molecular structure of ionic liquid on bubble behaviors

摘要

The complex interaction between cations and anions as well as the molecular structure makes the ionic liquids (ILs) different from organic solutions. Thus, the conventional hydrodynamic models, which are suitable for water and organic solutions, are not able to predict bubble behaviors in ILs accurately. In this work, a new FCCS (Fragment Contribution Corresponding State)-CFD(CFD) coupled method is proposed, so that the influence of molecular structure of ILs can be revealed. A source term which represents the electrostatic interaction between cations and anions of ILs is introduced into the momentum equation, which makes the model reflect strictly the inner feature of ionic liquids. The simulation results show that the relative error of aspect ratio is only 0.06%, much lower than 3.73% which is calculated by the conventional method, indicating the new method is more accurate. Furthermore, the bubble behaviors, i.e. the bubble shape and velocity, in 30 ILs are simulated. As a result, the relationship between molecular structures of ILs and bubble behaviors, as well as the bubble flow regime is obtained.