Flow of granular materials in a bladed mixer: Effect of particle properties and process parameters on impeller torque and power consumption

Boonkanokwong, Veerakiet; Frank, Rohan P.; Valliappan, Pavithra; Remy, Brenda; Khinast, Johannes G.; Glasser, Benjamin J.

doi:10.1016/j.apt.2018.07.022

Cited by 29 publications

(28 citation statements)

References 42 publications

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“…Mixers commonly used in industrial applications include bladed mixers [7,8], rotating drums [9,10], agitated filter beds [11,12], and fluidised beds [13,14]. However, bladed mixers (e.g., the overhead stirrers) possess the advantage of their simpler design and relatively shorter blending time [15].…”

Section: Introductionmentioning

confidence: 99%

“…However, bladed mixers (e.g., the overhead stirrers) possess the advantage of their simpler design and relatively shorter blending time [15]. Moreover, such mixers are extensively used in applications that require high input power, e.g., in blending solid pellets to melt and mix the polymer [7] and their blending performance was examined by many researchers [7,8,[16][17][18]. However, these studies focused mainly on the impeller torque and power consumption [7,8], flow behaviour [16,17], and heat transfer [18].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, such mixers are extensively used in applications that require high input power, e.g., in blending solid pellets to melt and mix the polymer [7] and their blending performance was examined by many researchers [7,8,[16][17][18]. However, these studies focused mainly on the impeller torque and power consumption [7,8], flow behaviour [16,17], and heat transfer [18]. Little attention was paid to the energy dissipation and thermal response of the granular bed.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of heat generation during the mixing of granular materials in an overhead stirrer

Kisuka

Rangel

Hare

et al. 2023

Preprint

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Bladed mixers are widely used for processing granular materials where significant mechanical energy is required to produce the desired blend. Some mechanical energy is dissipated within the granular medium, generating heat during this process. However, our knowledge of the heat generation mechanisms without external thermal loads is still lacking. This study uses an overhead stirrer to mix granular materials and investigate heat generation by monitoring the temperature changes in the granular bed. Additionally, first-order kinetic equations are used to extrapolate the experimental data to a thermal equilibrium where the heat generation and heat loss rates are equal. Lead, steel, and glass particles are used under various operating conditions. It is observed that metallic particles heat up faster owing to their lower heat capacity. Also, increasing the rotation speed, fill ratio and particle size result in a greater temperature increase. Moreover, flat blades induce more heat generation compared to tilted blades.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental investigation of heat generation during the mixing of granular materials in an overhead stirrer

Kisuka

Rangel

Hare

et al. 2023

Preprint

View full text Add to dashboard Cite

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“…The influence of impeller properties on the rate of mixing have also been examined. For example, Boonkanokwong et al 8 carried out experiments where they tested the mixing performance of impellers with different numbers of blades and several blade angles in a laboratory‐scale agitated dryer. Sahni et al 9 conducted a parametric investigation of the operating conditions that affect drying performance.…”

Section: Introductionmentioning

confidence: 99%

Infrared temperature measurements and DEM simulations of heat transfer in a bladed mixer

et al. 2022

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An understanding of heat transfer in a bladed mixer is important for drying of pharmaceutical drug crystals. This study presents thermal imaging experiments of the particle bed surface in a bladed mixer to investigate how the impeller speed influences the rate and the uniformity of heat transfer. Next, the process is simulated using the discrete element method. The bed thermal properties are lumped into an effective thermal conductivity, that is calibrated for one impeller speed. The experiments and the simulations show the same trends and generally agree well for all agitated beds. However, to obtain good agreement of the rate of heat transfer between the simulations and experiments in a static bed, we need to adopt a higher thermal conductivity than for the agitated beds. Finally, we discuss the implications of these results for the design of operating protocols.

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“…The results showed that the agitation speed had no significant influence on the shaft torque when the Froude number ( Fr ) was between 0.17 and 1.1. Boonkanokwong et al measured the shaft torque and power consumption when mixing monodisperse glass beads in a cylindrical stirred tank with flat blade impeller. It was found that the shaft torque and power consumption can be strongly related with the size, the friction coefficient and the filling level of particles, and the agitation speed of impeller, as well as its geometric dimensions.…”

Section: Introductionmentioning

confidence: 99%

Shaft Power Consumption of Stirred Tank with Particles: From the Perspective of Pseudoshearing Thinning Rheological Property of Particles

Bao

Liu

Yang

et al. 2022

Ind. Eng. Chem. Res.

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Accurately determining the shaft power consumption is important in the design and scale-up of stirred tanks with particles. Firstly, the apparent viscosity of the stirring particles is proposed. The effects of impeller type, agitation speed, and particle filling level on the apparent viscosity of the stirring particles are experimentally studied with various particles. It was found that larger particles, a greater friction coefficient between particles, and a higher particle filling level all result in a larger apparent viscosity of the particles. The stirred particles show shear thinning behavior, which is similar to the pseudoplastic non-Newtonian fluids. Finally, based on the force analysis and the concept of particles having an apparent viscosity, a model predicting the shaft power consumption in stirring noncohesive particles is proposed. The predicted shaft power in the stirred tank is within ±15% with particles of different sizes. When the model is applied to the 10-times scaled-up stirred tank with geometric similarity, the prediction results of the shaft power are within ±6%.

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Flow of granular materials in a bladed mixer: Effect of particle properties and process parameters on impeller torque and power consumption

Cited by 29 publications

References 42 publications

Experimental investigation of heat generation during the mixing of granular materials in an overhead stirrer

Experimental investigation of heat generation during the mixing of granular materials in an overhead stirrer

Infrared temperature measurements and DEM simulations of heat transfer in a bladed mixer

Shaft Power Consumption of Stirred Tank with Particles: From the Perspective of Pseudoshearing Thinning Rheological Property of Particles

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