Transition to Taylor Vortex Flow Between Rotating Conical Cylinders

Li, Qiushu; Wen, Pu; Xu, Lanxi

doi:10.1016/s1001-6058(09)60050-0

Cited by 15 publications

(8 citation statements)

References 13 publications

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“…Furthermore, Taylor vortices can appear in the flow field when the Taylor number (Ta) exceeds some critical value (Ta cr ), which depends on the Reynolds number of flow. Taylor vortices have been experimentally observed for Reynolds number above 800 (Li et al, 2010). Simple calculations show that our emulsions prepared at 10 and 30 wt% oil will break due to Taylor vortices (Almeida-Rivera and Bongers, 2010) and not due to shearing in simple shear flow ( Fig.…”

Section: Drop Breakage and Coalescence In Colloid Millsmentioning

confidence: 58%

Prediction of emulsion drop size distributions in colloid mills

Maindarkar

Dubbelboer

Meuldijk

et al. 2014

Chemical Engineering Science

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Developed a population balance equation model for emulsification in colloid mill. Derived the function for drop breakage frequency in simple shear flow. Proposed a new daughter drop distribution function for capillary drop breakage. Used a viscosity model to predict the emulsion viscosity at high shear rates. Demonstrated good agreement between measured and predicted drop size distributions. Colloid mills are the most common emulsification devices used in industry for products with high oil content. Drop breakage occurs when the emulsion is flowed through a small gap between rotor and stator under laminar shear conditions. In this paper, we have developed the first full population balance equation (PBE) model for colloid mills and used the model to better understand the relevant drop breakage mechanisms. The PBE model accounted for both drop breakage and coalescence and generated predictions of the drop size distribution after each pass of the emulsion through the colloid mill. Drops were assumed to break due to capillary instability with the distribution of drop sizes resulting from each breakage event studied in detail. A viscosity model was developed to predict the emulsion viscosity as function of the oil fraction and the high shear rates commonly used. Nonlinear optimization was used to estimate adjustable parameters in the breakage and coalescence functions to minimize the least-squares difference between predicted and measured drop size distributions for high oil-to-surfactant emulsions. We concluded that experimentally observed drop volume distributions could not be predicted with daughter drop distribution functions reported in the literature. Improved predictions were obtained using a new bimodal distribution function which captured drop breakage into multiple, nearly uniform daughter drops with a large number of small satellite drops. We also investigated model extensibility for changes in the oil fraction, emulsion flow rate and rotor speed.Published by Elsevier Ltd.

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Section: Drop Breakage and Coalescence In Colloid Millsmentioning

confidence: 58%

Prediction of emulsion drop size distributions in colloid mills

Maindarkar

Dubbelboer

Meuldijk

et al. 2014

Chemical Engineering Science

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“…So far, the studies of the flow in RLFR have not been given due attention. However, for the upside down device of with the inner one rotating and the outer one at rest have been experimentally studied by Wimmer [4,5] and numerically by Noui-Mehidi et al [6,7], Xu et al [8,9] and Li et al [10]. In [4,5] Wimmer studied the stability of basic flow and the transition to Taylor vortices, as well as the occurrence of Taylor vortex at different geometries.…”

Section: R Rmentioning

confidence: 99%

Dimensional and Mechanical Similarity Analysis of the Flow in Rotating Liquid Film Reactor

Li¹,

Xu²,

Zhang³

et al. 2013

OJFD

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A rotating liquid film reactor (RLFR) is a device of two coaxial rotating conical cylinders with the inner cone rotating and the outer one stationary. A complete mathematical model for the flow between the conical cylinders is built and a dimensional analysis is carried out. It is proved that at each point of the flow field the dimensionless pressure and velocity of the flow are determined by parameters: Reynolds number (Re), aspect ratio (Γ), radius ratio (η) and wall inclination angle (α). Furthermore, a sufficient and a necessary condition are derived for mechanical similarity between RLFR and a manufacturing equipment being geometrically similar to RLFR. Finally, a numerical simulation for the distribution of pressure and velocity is performed. The results may provide a theoretical basis for experiment method and numerical simulation of the flow in a RLFR-like device.

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“…Such exchange processes are largely controlled by the chemical composition and physical properties of particles (Fu et al, 2009). Hydrodynamic-induced turbulence in shallow lakes appears to have a significant influence on the exchange between sediment and water and it can increase the suspension of sediment particles and even promote the outward movement of P dissolved in pore water (Bowes et al, 2008;Li et al, 2010). The P release from the sediment to the lake water occurs either as the mobilization of P from suspended sediment particles or after mobilization into the dissolved P-pool in sediment pore water and the subsequent upward transport of the dissolved species into the water (Sun et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Critical velocity in phosphorus exchange processes across the sediment-water interface

Wan¹,

Wang²,

Li³

et al. 2013

Journal of Environmental Sciences

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Sediments are ultimate sinks of nutrients in lakes that record the pollution history evolutionary processes, and anthropogenic activities of a lake. However, sediments are considered as inner sources of environmental factor changes such as the variation in hydrodynamic conditions because of the nutrients they release. How does this process happen? This study investigates a typical nutrient phosphorus (P) exchange among sediment, suspended particle matter (SPM), and water. Compared with numerical and experimental studies, this study confirms that the critical velocity that occurs at a lower flow rate state exists in the range of 7 to 15 cm/sec. Critical velocity below the critical flow rate promotes the migration of particulate phosphorus (PP) to the SPM. On the other hand, critical velocity above the critical flow rate promotes the release of PP in water.

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Transition to Taylor Vortex Flow Between Rotating Conical Cylinders

Cited by 15 publications

References 13 publications

Prediction of emulsion drop size distributions in colloid mills

Prediction of emulsion drop size distributions in colloid mills

Dimensional and Mechanical Similarity Analysis of the Flow in Rotating Liquid Film Reactor

Critical velocity in phosphorus exchange processes across the sediment-water interface

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