Estimation Of Physical Properties Of Ionic Liquids And Study On The Flow Characteristics Of Ionic Liquid Ethanol Solutions In Microtubes

Due to high heat and mass transfer efficiency, easy to scale up and large safety margin, micro-chemical technology has a promising application in the production of hazardous chemical products and high exothermic reactions. The flow characteristic of fluid flow in microtubes is crucial for the design and optimization of micro-chemical devices, such as micro heat exchanger and micro reactor. As a novel green solvent with high designability, ionic liquid is a promising alternative for traditional organic solvents in chemical industry, therefore, study on the physical properties and flow characteristic of ionic liquid in microtubes is of great importance for the industrialization of ionic liquid and the design of micro-chemical devices.When fluid with ions contacts with the surface of a microtube, static charge will generates on the surface, leading to the redistribution of positive and negative charges within the fluid and the formation of electrical double layer near the surface. The electrical double layer then generates the electro-viscous effect which blocks the fluid flow and may significantly influence the fluid flow in microtube when the scale of microtube is very small. Using ethanol and [C2mim][EtSO4] ethanol solution with five different concentrations as working fluid, the laminar flow in stainless steel microtubes with three different diameters were studied, and the influences of electro-viscous effect on their flow were also investigated in in this paper.The main contents are generalized as follows:(1) A group contribution method based on27groups was developed for the estimation of static dielectric constant of ionic liquid as it is a key parameter in the study of electro-viscous effect on micro flow. The correlation of128data points of58ionic liquids gives an average absolute relative deviation of7.41%, which is much lower than that of the models developed by other researchers. The method proposed in this paper provides a simple but reliable approach for the estimation of static dielectric constant of ionic liquids at different temperatures.(2) Based on Erying reaction theory and free volume theory, a new group contribution method was developed for the estimation of electrical conductivity of ionic liquid as it is also a key parameter in the study of electro-viscous effect on micro flow. An average absolute relative deviation of7.89%is obtained for the correlation of1016data points of124ionic liquids. The electrical conductivities of3ionic liquids at various temperatures were calculated with th model to verify its reliability for the estimation of electrical conductivity of ionic liquid.(3) The density and viscosity of [C2mim][EtSO4] ethanol solutions at285.15-313.151were experimentally determined. Then using ethanol and10"6mol/L,10-5mol/L,10-4mol/L,10mol/L as well as O.lmol/L [C2mim][EtSO4] ethanol solution as working fluid, the laminar flo(?) in stainless steel microtubes with0.353mm、0.254mm and0.129mm inner diameters wer studied, and the influences of electro-viscous effect on their flow were also investigated in thi paper.