Study of kneading pressure and power consumption in a twin-blade planetary mixer for mixing highly viscous fluids

Long, Jiecai; He, Yu; Zhan, Xueying; Sun, Zhuang; Shen, Baojun; Li, Xiwen

doi:10.1016/j.ces.2021.116723

Cited by 8 publications

(8 citation statements)

References 39 publications

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“…It is of great significance to investigate the correlation of the process parameters with the kneading pressure in engineering applications. According to a previous study, 17 when mixing high viscosity Newtonian fluids in a twin‐blade planetary mixer, the kneading pressure characteristic was developed by proposing the pressure number

N_{p_{\max}}

and the pressure‐oriented Reynolds number Re M‐p , which can be rewritten as follows:

N_{p_{\max}} = K_{p_{\max}} / {italicRe}_{M - p}

in which

{italicRe}_{M - p} = \frac{ρ u_{ch - p} d_{G}}{μ}

N_{p_{\max}} = \frac{p_{\max}}{ρ {u_{italicch - p}}^{2}}

u_{ch - p} = \frac{3}{2} N_{R} d_{R}

where ρ and μ refer to the density and viscosity of the fluids respectively, u ch ‐ p refers to the pressure‐oriented characteristic velocity, and

K_{p_{\max}}

denotes the pressure‐oriented constant parameter, which is equal to 399.41.…”

Section: Resultsmentioning

confidence: 99%

“…According to a previous study, 17 when mixing high viscosity Newtonian fluids in a twin-blade planetary mixer, the kneading pressure characteristic was developed by proposing the pressure number N p max and the pressure-oriented Reynolds number Re M-p , which can be rewritten as follows:…”

Section: Correlation For Kneading Pressurementioning

confidence: 99%

“…When mixing high viscosity Newtonian fluids in a twin-blade planetary mixer, the improved power number N pi and Reynolds number Re i were proposed to determine the correlation of the power consumption in a previous study. 17 They are expressed as follows:…”

Section: Correlation For Power Consumptionmentioning

confidence: 99%

“…[7][8][9][10][11][12][13] By modifying the power number and Reynolds number, André et al 14 revealed the effect of the process parameters on the power consumption of a planetary mixer for homogenizing granular materials, and Delaplace et al 15,16 derived a power curve of a TRIAXE ® system with Newtonian fluids. Similarly, by proposing the improved power number, improved Reynolds number, pressure number, and pressure-oriented Reynolds number, Long et al 17 obtained the correlations of the motion parameters with the power consumption and kneading pressure for a twin-blade planetary mixer involving Newtonian fluids. For mixing non-Newtonian fluids, in addition to the modified power and Reynolds numbers, other two parameters, namely, the effective viscosity and the effective shear rate, were proposed by Auger et al 18,19 to predict the power consumption of a planetary mixer with a helicoidal dough hook.…”

Section: Introductionmentioning

confidence: 99%

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Study of hydrodynamics and flow characteristics in a twin‐blade planetary mixer with non‐Newtonian fluids

et al. 2022

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This study aims to characterize the hydrodynamics and flow characteristics in a twin‐blade planetary mixer with non‐Newtonian fluids by using CFD modeling technique. The kneading pressure was recorded using an experimental setup, and a CFD model was verified. The flow characteristics and hydrodynamics in the mixing vessel containing the power‐law fluids were analyzed quantitatively, particularly the influence of the flow behavior index n. Results revealed that as n increased from 0.25 to 1.75, the maximum shear rate decreased from 733 to 120 s−1 and the local apparent viscosity in the kneading regions increased significantly. The maximum kneading pressure and power consumption increased almost exponentially with increasing n. The correlation for the kneading pressure and the correlation for the power consumption were established by introducing the pressure‐oriented effective viscosity μe‐p, the pressure‐oriented effective shear rate trueγ̇e−p, the improved effective viscosity μei and the improved effective shear rate trueγ̇italicei.

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N_{p_{\max}}

and the pressure‐oriented Reynolds number Re M‐p , which can be rewritten as follows:

N_{p_{\max}} = K_{p_{\max}} / {italicRe}_{M - p}

in which

{italicRe}_{M - p} = \frac{ρ u_{ch - p} d_{G}}{μ}

N_{p_{\max}} = \frac{p_{\max}}{ρ {u_{italicch - p}}^{2}}

u_{ch - p} = \frac{3}{2} N_{R} d_{R}

where ρ and μ refer to the density and viscosity of the fluids respectively, u ch ‐ p refers to the pressure‐oriented characteristic velocity, and

K_{p_{\max}}

denotes the pressure‐oriented constant parameter, which is equal to 399.41.…”

Section: Resultsmentioning

confidence: 99%

Section: Correlation For Kneading Pressurementioning

confidence: 99%

Section: Correlation For Power Consumptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of hydrodynamics and flow characteristics in a twin‐blade planetary mixer with non‐Newtonian fluids

et al. 2022

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“…This method targets the structural changes by secondary forces, such as H-bonds, conformational energies, or hydrophobic interactions [27,28]. Even though this method uses an open system and is difficult to reproduce due to manual manipulation, many publications report that this method belongs to one of the best complex preparation methods.…”

Section: Complexation With Kneadingmentioning

confidence: 99%

Toward a Greener World—Cyclodextrin Derivatization by Mechanochemistry

Jicsinszky

Cravotto

2021

Molecules

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Cyclodextrin (CD) derivatives are a challenge, mainly due to solubility problems. In many cases, the synthesis of CD derivatives requires high-boiling solvents, whereas the product isolation from the aqueous methods often requires energy-intensive processes. Complex formation faces similar challenges in that it involves interacting materials with conflicting properties. However, many authors also refer to the formation of non-covalent bonds, such as the formation of inclusion complexes or metal–organic networks, as reactions or synthesis, which makes it difficult to classify the technical papers. In many cases, the solubility of both the starting material and the product in the same solvent differs significantly. The sweetest point of mechanochemistry is the reduced demand or complete elimination of solvents from the synthesis. The lack of solvents can make syntheses more economical and greener. The limited molecular movements in solid-state allow the preparation of CD derivatives, which are difficult to produce under solvent reaction conditions. A mechanochemical reaction generally has a higher reagent utilization rate. When the reaction yields a good guest co-product, solvent-free conditions can be slower than in solution conditions. Regioselective syntheses of per-6-amino and alkylthio-CD derivatives or insoluble cyclodextrin polymers and nanosponges are good examples of what a greener technology can offer through solvent-free reaction conditions. In the case of thiolated CD derivatives, the absence of solvents results in significant suppression of the thiol group oxidation, too. The insoluble polymer synthesis is also more efficient when using the same molar ratio of the reagents as the solution reaction. Solid reactants not only reduce the chance of hydrolysis of multifunctional reactants or side reactions, but the spatial proximity of macrocycles also reduces the length of the spacing formed by the crosslinker. The structure of insoluble polymers of the mechanochemical reactions generally is more compact, with fewer and shorter hydrophilic arms than the products of the solution reactions.

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Hydrodynamics and film formation characteristics in a horizontal self‐cleaning twin‐shaft kneader for polymer devolatilization

Liao

Hong³

et al. 2022

J of Applied Polymer Sci

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A deep understanding of hydrodynamics and film formation characteristics is a prerequisite for the design of twin‐shaft kneaders. In this work, the hydrodynamics and film formation characteristics of a self‐cleaning twin‐shaft kneader are investigated using computational fluid dynamics method. Because of the intermeshing interaction and scratching action of the kneader rods, both bounded films and free films coexist in the kneader. Since both shafts rotate clockwise, more liquid is accumulated in the left cylinder. The liquid level of the left cylinder is higher which reduces the film formation rate of the left zone. The film formation rate in the right zone is 1.3–1.8 times that of the left zone and overlapping zone. The differences between the left and right cylinders would cause inconsistent devolatilization performances. To reduce the negative effects of asymmetric level, a static kneading rod is used to reduce the liquid level of the left zone and increase the film formation rate by 15%. We notice that adding a static kneading rod reduces the power consumption by 10%–30% compared with increasing the rotating speed to the same film formation rate. It could be an efficient method for polymer devolatilization.

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Study of kneading pressure and power consumption in a twin-blade planetary mixer for mixing highly viscous fluids

Cited by 8 publications

References 39 publications

Study of hydrodynamics and flow characteristics in a twin‐blade planetary mixer with non‐Newtonian fluids

Study of hydrodynamics and flow characteristics in a twin‐blade planetary mixer with non‐Newtonian fluids

Toward a Greener World—Cyclodextrin Derivatization by Mechanochemistry

Hydrodynamics and film formation characteristics in a horizontal self‐cleaning twin‐shaft kneader for polymer devolatilization

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