Mixing enhancement using chaos theory in fluid dynamics: Experimental and numerical study

Shirmohammadi, Fatemeh; Tohidi, A.

doi:10.1016/j.cherd.2018.04.007

Cited by 12 publications

(7 citation statements)

References 10 publications

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“…The displacement of these fluid particles obtained by increasing the jets' Reynolds number is known to improve mixing performance. 40 The visualization results of plane-3, presented in Figure 8, prove that at Re = 60, the inertia forces of fluid streams incoming from the jets are enough to form the half vortex pattern. With increasing Re = 60 to Re = 80, elliptic regions indicating dead zones started to occur.…”

Section: Piv Setup and Measurementsmentioning

confidence: 78%

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Gas Flow Hydrodynamics in Vortex Mixers: Flow Visualization and PIV Flow Field Characterization

Gecim

Erkoç

2021

Ind. Eng. Chem. Res.

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The gas flow hydrodynamics in a vortex mixer was investigated using flow visualization and particle image velocimetry (PIV) techniques for several Reynolds numbers ranging from Re = 20 to 280 and equal momentum of the jets. The flow regime transition of two methane gas streams coming from two tangential jets was analyzed by the detection of the critical Reynolds number of the flow. This critical point was determined from time-averaged and instantaneous flow images, velocity fluctuations, and hence turbulence intensity values of the vortex mixer. Results show that the flow gained the swirl motion at Re = 70 and the instabilities in the flow started at around Re = 230, where the gas flow hydrodynamics was diffusion controlled. Beyond Re = 230, the flow was unsteady and chaotic flow overruled the molecular diffusion and the ensemble mixing of the gases dependent on the convection was achieved starting from this point. This study sheds light on the gas flow hydrodynamics of a vortex mixer and points out the flow regime transitions.

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Section: Piv Setup and Measurementsmentioning

confidence: 78%

“…However, as the Reynolds number increased, the flow regime changed at around Re = 230, and these elliptic regions started to disappear. The displacement of these fluid particles obtained by increasing the jets’ Reynolds number is known to improve mixing performance …”

Section: Resultsmentioning

confidence: 99%

Gas Flow Hydrodynamics in Vortex Mixers: Flow Visualization and PIV Flow Field Characterization

Gecim

Erkoç

2021

Ind. Eng. Chem. Res.

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“…The bifurcation analysis demonstrates how the system transitions to a chaotic regime and the period-doubling exhibited by the respective bifurcations. The applications of this novel chaotic system is very wide an can be implemented for the mathematical modeling of phenomenons found in meteorology [ 79 ], astrophysics [ 80 ], fluid dynamics [ 81 ], and in other engineering related systems such as electrical and power, mechanical, mechatronics, and chemical systems. The reason of the applicability of this novel chaotic system is that by estimating the right parameters and considering some topological aspects such as the limit set related to the unstable limit cycle and the domain of attraction this chaotic system can be implemented in the mathematical modeling of different types of phenomena.…”

Section: Definition Of the Novel Chaotic Systemmentioning

confidence: 99%

Robust Stabilization and Synchronization of a Novel Chaotic System with Input Saturation Constraints

Azar

Serrano

Zhu

et al. 2021

Entropy

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In this paper, the robust stabilization and synchronization of a novel chaotic system are presented. First, a novel chaotic system is presented in which this system is realized by implementing a sigmoidal function to generate the chaotic behavior of this analyzed system. A bifurcation analysis is provided in which by varying three parameters of this chaotic system, the respective bifurcations plots are generated and evinced to analyze and verify when this system is in the stability region or in a chaotic regimen. Then, a robust controller is designed to drive the system variables from the chaotic regimen to stability so that these variables reach the equilibrium point in finite time. The robust controller is obtained by selecting an appropriate robust control Lyapunov function to obtain the resulting control law. For synchronization purposes, the novel chaotic system designed in this study is used as a drive and response system, considering that the error variable is implemented in a robust control Lyapunov function to drive this error variable to zero in finite time. In the control law design for stabilization and synchronization purposes, an extra state is provided to ensure that the saturated input sector condition must be mathematically tractable. A numerical experiment and simulation results are evinced, along with the respective discussion and conclusion.

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“…The purpose of this paper was to numerically and experimentally examine the effect of chaotic flow on the mixing of a highly viscous fluid and reducing the time and energy necessary for achieving the required homogeneous mixing. In our previous study (Shirmohammadi and Tohidi, 2018), the effect of chaotic flow was studied on the mixing of highly viscous fluids. It was shown that mixing will be very poor if the rotors rotate with the same and constant speed.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Analysis of Chaotic Advection as an Efficient Approach to Maximize Homogeneous Laminar Mixing in a Batch Mixer

Shirmohammadi

Tohidi

2019

Braz. J. Chem. Eng.

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In the present work, the impacts of effective parameters on the mixing of Stokes flows in a chaotic batch mixer are numerically and experimentally studied. The batch mixer consists of a container and two circular rotors where the rotors can rotate independently. To investigate the possibility of improving the mixing, the effect of nonconstant speeds, contra-rotating rotors, and varying rotor speeds are studied. The results showed that varying the rotor speed while rotating in the same direction does not significantly increase mixing. However, if the rotors rotate in opposite directions, 10-times more mixing is achieved compared to the mode of rotating in the same direction. Nevertheless, given the constant speed of rotors, the flow is steady since the fluid particles have periodic movements in secondary flows, but the flow becomes chaotic and mixing is considerably increased by applying sinusoidal perturbations to the rotor speed. Nevertheless, for both modes of rotations in the same and opposite directions, the chaotic flow leads to increased mixing index in the same amount of time. Based on results, the best mixing results are achieved when the rotors rotate with sinusoidal rotational speed in opposite directions.

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Mixing enhancement using chaos theory in fluid dynamics: Experimental and numerical study

Cited by 12 publications

References 10 publications

Gas Flow Hydrodynamics in Vortex Mixers: Flow Visualization and PIV Flow Field Characterization

Gas Flow Hydrodynamics in Vortex Mixers: Flow Visualization and PIV Flow Field Characterization

Robust Stabilization and Synchronization of a Novel Chaotic System with Input Saturation Constraints

Experimental and Numerical Analysis of Chaotic Advection as an Efficient Approach to Maximize Homogeneous Laminar Mixing in a Batch Mixer

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