Abstract:In liquid-liquid extraction contractors, mass transfer and stage efficiency are closely related to drop hydrodynamics. In the present study, hydrodynamic simulation of three standard liquid-liquid extraction systems recommended by the EFCE (European Federation of Chemical Engineering) has been investigated. Toluene/water, n-butyl acetate/water, and n-butanol/water with different drop diameters were considered in the simulations, representing systems with high, medium, and low interfacial tension respectively. … Show more
“…Multiphase is mentioned according to the VOF approach, which may exist in liquidgas or liquid-liquid interactions, with our case being a type of separate system; in other words, it is a continuous flow, such as in the case of water with oil. It is called a phase if it is in a state or if it is the place it occupies (dispersed or continuous), as in the experiments carried out using VOF simulation for single rising drops in three liquid-liquid extraction systems using csf and css interfacial force models [23]; this included water and n-butanol, water-n.butyl acetate, and water-toluene, where water constituted the continuous phase in all cases, and the other components constituted the dispersed phase [24].…”
The following article proposes the design of a bi-centrifugal atomizer that allows the interaction of sprays from two fluids (water and liquid nitrogen). The liquid nitrogen (LN2) is below −195.8 °C, a temperature low enough for the nitrogen, upon contact with the atomized water, to cause heat loss and bring it to its freezing point. The objective is to convert the water droplets present in the spray into ice. Upon falling, the ice particles can be dispersed, covering the largest possible area of the seafood products intended for cold preservation. All these phenomena related to the interaction of two fluids and heat exchange are due to the bi-centrifugal atomizer, which positions the two centrifugal atomizers concentrically, resulting in the inevitable collision of the two sprays. Each of these atomizers will be designed using a mathematical model and CFDs tools. The latter will provide a better study of the flow behavior of both fluids inside and outside the bi-centrifugal atomizer. Hence, the objective revolves around confirming the validity of the mathematical model through a comparison with numerical simulation data. This comparison establishes a strong correlation (with a maximum variance of 1.94% for the water atomizer and 10% for the LN2 atomizer), thereby ensuring precise manufacturing specifications for the atomizers. It is important to highlight that, in order to achieve the enhanced resolution and comprehension of the fluid both inside and outside the duplex atomizer, two types of meshes were utilized, ensuring the utilization of the optimal option. Similarly, the aforementioned meshes were generated using two distinct software platforms, namely ANSYS Meshing (tetrahedral mesh) and ANSYS ICEM (hexahedral mesh), to facilitate a comparative analysis of the mesh quality obtained. This comprehension facilitated the observation of water temperature during its interaction with liquid nitrogen, ultimately ensuring the freezing of water droplets at the atomizer’s outlet. This objective aligns seamlessly with the primary goal of this study, which revolves around the preservation of seafood products through cold techniques. This particular attribute holds potential for various applications, including cooling processes for food products.
“…Multiphase is mentioned according to the VOF approach, which may exist in liquidgas or liquid-liquid interactions, with our case being a type of separate system; in other words, it is a continuous flow, such as in the case of water with oil. It is called a phase if it is in a state or if it is the place it occupies (dispersed or continuous), as in the experiments carried out using VOF simulation for single rising drops in three liquid-liquid extraction systems using csf and css interfacial force models [23]; this included water and n-butanol, water-n.butyl acetate, and water-toluene, where water constituted the continuous phase in all cases, and the other components constituted the dispersed phase [24].…”
The following article proposes the design of a bi-centrifugal atomizer that allows the interaction of sprays from two fluids (water and liquid nitrogen). The liquid nitrogen (LN2) is below −195.8 °C, a temperature low enough for the nitrogen, upon contact with the atomized water, to cause heat loss and bring it to its freezing point. The objective is to convert the water droplets present in the spray into ice. Upon falling, the ice particles can be dispersed, covering the largest possible area of the seafood products intended for cold preservation. All these phenomena related to the interaction of two fluids and heat exchange are due to the bi-centrifugal atomizer, which positions the two centrifugal atomizers concentrically, resulting in the inevitable collision of the two sprays. Each of these atomizers will be designed using a mathematical model and CFDs tools. The latter will provide a better study of the flow behavior of both fluids inside and outside the bi-centrifugal atomizer. Hence, the objective revolves around confirming the validity of the mathematical model through a comparison with numerical simulation data. This comparison establishes a strong correlation (with a maximum variance of 1.94% for the water atomizer and 10% for the LN2 atomizer), thereby ensuring precise manufacturing specifications for the atomizers. It is important to highlight that, in order to achieve the enhanced resolution and comprehension of the fluid both inside and outside the duplex atomizer, two types of meshes were utilized, ensuring the utilization of the optimal option. Similarly, the aforementioned meshes were generated using two distinct software platforms, namely ANSYS Meshing (tetrahedral mesh) and ANSYS ICEM (hexahedral mesh), to facilitate a comparative analysis of the mesh quality obtained. This comprehension facilitated the observation of water temperature during its interaction with liquid nitrogen, ultimately ensuring the freezing of water droplets at the atomizer’s outlet. This objective aligns seamlessly with the primary goal of this study, which revolves around the preservation of seafood products through cold techniques. This particular attribute holds potential for various applications, including cooling processes for food products.
“…Literature review shows that several researchers investigated the BR behaviors in a full two‐dimensional (2D) computational domain . Here, a 2D domain is selected since the present study is mainly focused on the BR characterization in a high Mo case.…”
The bubble rising (BR) dynamic is a common phenomenon in numerous processes of industries. Here, a single air BR behavior is studied using computational fluid dynamics (CFD) modelling in a Newtonian fluid (NF) and non-Newtonian fluid (nNF). The volume of fluid formulation with the continuum surface force equation is used to track the air bubble in a NF, while the viscosity of the nNF fluid is estimated by using the power-law equation. The bubble terminal velocity and its shape deformation, as well as the influence of different dimensionless numbers on BR characterization are investigated. The bubble rise in NF, the bubble terminal velocity increases with decreasing Morton number, and bubble moves up in a zigzag way with shape oscillation for the case of low Morton number of the NF. The bubble rise in nNF, the bubble terminal velocity increases with the increases in the rheological index, and bubble size as well as its shape transforms from an ellipsoidal to ellipsoidal cap types.It is found that the drag coefficient is high in a low rheological index compared with the high rheological index. The CFD results are compared with experimental results and empirical correlations reported in the literature. Good agreements are found between the CFD and the literature data for both fluids.
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