Local hydrodynamics investigation within a dynamic filtration unit under laminar flow

Xie, Xiaowen; Dietrich, Nicolas; Fillaudeau, Luc; Men, Claude Le; Schmitz, Philippe; Liné, Alain

doi:10.1016/j.cherd.2018.02.018

Cited by 7 publications

(10 citation statements)

References 28 publications

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“…Let us recall the criterion for the identification of oscillatory modes of the flow in stirred tanks 15,49,59 that we shall use as a starting point for our analysis. Oscillatory components are the results of coupled modes for which: two successive eigenvalue values are close to each other in the eigenvalue spectrum (the coupled modes have the same energetic impact). the temporal coefficient of each mode i, θ i ( t ), shows a sinusoidal trend when plotted versus time, and its PDF is shaped like that of a sinusoidal function (while that of a turbulent mode approaches a Gaussian shape (as discussed later in Figure 6).…”

Section: Resultsmentioning

confidence: 99%

“…Its main advantage is that it requires only a small number of velocity field sampled ( N in Equation )) and no knowledge of the blade position for each recorded field, while phase resolved measurements require complex timing set‐ups and the accumulation of much more instantaneous fields in order to achieve statistical convergence for each blade position. By analogy to this blade stirred tank case, applying POD to the oscillating grid flow should provide information on turbulence and coherent structures in a much quicker and less data‐consuming fashion than the phase averaged measurements detailed in, 40 and identify modes that correspond to the oscillatory component of the flow 5,15,49,59 …”

Section: Methodsmentioning

confidence: 99%

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POD analysis of oscillating grid turbulence in water and shear thinning polymer solution

et al. 2020

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Oscillating grids are frequently used with water and Newtonian fluids to generate controlled turbulence and mixing. Yet, their use with shear thinning fluids still requires experimental characterization. Proper orthogonal decomposition (POD) is applied to PIV measurements of the flow generated by an oscillating grid in water and a shear thinning dilute polymer solution (DPS) of xanthan gum. The aims are to investigate the ability of POD to isolate periodic flow structures, and to use it to describe the effects of the shear thinning property. A dominance of the low order POD modes is evidenced in DPS. The methods applied in blade stirred tanks to identify oscillatory motion fail here. However, a strong mode coupling in the grid swept region is observed, determined by the working fluid and by an underlying chaotic nature of the flow. Possibilities of reconstructing turbulence properties using high order modes are discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

POD analysis of oscillating grid turbulence in water and shear thinning polymer solution

et al. 2020

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“…PIV is a reliable measurement technique for obtaining local and instantaneous velocity fields . It is based on the tracing of flow tracer spatial displacement to calculate the flow velocity . In this study, a 2D PIV system (LaVision, German) is used to measure velocity vectors and vorticity.…”

Section: Methodsmentioning

confidence: 99%

Investigation on Drag Reduction Characteristics and Shell‐Side Hydrodynamics in Hollow Fiber Membrane Modules

Zhang

Guo

et al. 2018

Advcd Theory and Sims

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A novel hollow fiber membrane module shell-side model is fabricated, simulated, tested, and analyzed. The mathematical model consists of a six spaced bar-shaped fiber and a vortex-control tangential entrance with protuberance radians. The vortex shedding behavior is captured by the digital particle image velocimetry technique. The velocity vectors and vorticity fields are analyzed experimentally. Meanwhile, the k − ε turbulent model is established to identify the flow stagnate point/region transformation. Investigation of wall shear stress and surface pressure distributions around circular cylindrical fibers illustrate the mechanism of drag reduction tentatively. Afterward, the novel optimization module produces higher recovery rates of up to 1.56 times as compared to that of a conventional module in equivalent filtration condition. It indicates that by means of a hydrodynamics flow control strategy, the fabricated membrane module structure could potentially improve energy utilization efficiency in filtration processes.

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“…Later, a model proposed by Moore [? ] calculated the thickness of the film with the Péclet number according to Equation (14).…”

Section: Comparison With Modelsmentioning

confidence: 99%

Gas–Liquid Mass Transfer around a Rising Bubble: Combined Effect of Rheology and Surfactant

Lebrun

Men

et al. 2021

Fluids

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The influence of viscosity and surface tension on oxygen transfer was investigated using planar laser-induced fluorescence with inhibition (PLIF-I). The surface tension and the viscosity were modified using Triton X-100 and polyacrylamide, respectively. Changes in the hydrodynamic parameters of millimetric bubbles were identified, and transfer parameters were calculated. The results revealed a decrease in the mass transferred in the presence of a contaminant. For modified viscosity, the decrease in mass transferred was allowed for by current correlations, but the presence of surfactant led to a sharp decrease in the liquid side mass transfer coefficient, which became even lower when polymer was added. An explanation for the gap between classical correlations and experimental values of kL is discussed, and a hypothesis of the existence of an accumulation of contaminant in the diffusion layer is proposed. This led to the possibility of a decrease in the diffusion coefficient and oxygen saturation concentration in the liquid film, explaining the discrepancy between models and experience. Adapted values of DO2 and [O2] * in this layer were estimated. This original study unravels the complexity of mass transfer from an air bubble in a complex medium.

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Local hydrodynamics investigation within a dynamic filtration unit under laminar flow

Cited by 7 publications

References 28 publications

POD analysis of oscillating grid turbulence in water and shear thinning polymer solution

POD analysis of oscillating grid turbulence in water and shear thinning polymer solution

Investigation on Drag Reduction Characteristics and Shell‐Side Hydrodynamics in Hollow Fiber Membrane Modules

Gas–Liquid Mass Transfer around a Rising Bubble: Combined Effect of Rheology and Surfactant

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