Novel drag coefficient models of ionic liquid – spherical particle system. (31st August 2019)

• Record Type: Journal Article
• Authors: Tang, Qi; Qin, Xueying; Dong, Haifeng; Zhang, Xiangping; Wang, Xiaodong; Wang, Kuisheng
• Is Part Of: Chemical engineering science. Volume 204(2019)
• Page Start: 177
• Page End: 185
• Publication Date: 2019-08-31
• Subjects: Drag coefficient (CD) -- Ionic liquids (ILs) -- Particle -- Correlation -- Interfacial tension; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2019.04.017
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Some typical CD models are not suitable for IL-particle system upon most occasions. Two novel CD models between ILs and a spherical particle are developed. The effect of interfacial tension on CD is first evaluated in the IL-particle system. The new models are significant for studying hydrodynamics of IL-particle systems. Abstract: Ionic liquids (ILs) have been proved to be excellently potential catalysts and solvents in a few chemical processes. In order to provide fundamental data for the reactor design and process optimization, it is essential to investigate the hydrodynamics and the mass transfer phenomena of liquid-solid two-phase systems containing ILs. In this work, we focus on the investigation of the hydrodynamic properties of a spherical particle in ILs, and a series of experiments are implemented in a cylindrical bubble column with three different diameters of spherical particles made of borosilicate glass (2 mm, 3 mm and 4 mm) in three kinds of ILs ([Bmim][BF4 ], [Bmim][PF6 ] and [Bmim][Tf2 N]). Moreover, Two key physical quantities (terminal velocity of particle and contact angle) are measured with a high-speed camera system and an automatic contact angle meter. Based on dimensional analysis, two novel empirical models of the drag coefficient ( CD ) between a spherical particle and ILs are developed in the range of particle's Reynolds number ( Re ) from 0.1 to 85. The first model is simple and the calculated CD agrees fairly well with the experimental data. Furthermore, in order to evaluate the effects of surface properties on CD, a newly defined dimensionless number ( Mo ′) is introduced into IL-particle flow studies for the first time, which comes into being a more rigorous model. The average predicted deviations of the two models are ±1.1% and ±1.5% respectively, which is much lower than that of contrastive models in the same situations (about 13.3% or more). These two models are significant for studying the hydrodynamics and mass transfer characteristics of IL-particle systems as well as the fluid dynamics simulation in related reactors.