Discrete element simulation study of a Freeman powder rheometer

Bharadwaj, Rahul; Ketterhagen, William R.; Hancock, Bruno C.

doi:10.1016/j.ces.2010.04.002

Cited by 99 publications

(49 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wilkinson et al (2017) analysed the flowability of powder in the FT4 using DEM and varied five input parameters (the static and rolling friction coefficients, coefficient of restitution, Young's modulus, and the cohesion energy density). They confirmed the findings of Bharadwaj et al (2010) and Hare et al ( , 2017, and found the static and rolling friction parameters play a critical role in the determination of the basic flow energy (BFE) and the specific energy (SE) of the powder bed. In addition, the cohesion energy density between particles also played a significant role in the change of BFE.…”

Section: Powder Flow By Mechanical Forcesupporting

confidence: 70%

“…However, the understanding of the flow mechanism of the powder rheometer has been requested, and many researchers have experimentally and numerically examined the flowability of powder in the FT4 (Bharadwaj et al 2010 and others). Bharadwaj et al (2010) have investigated the flow of non-cohesive particles in the FT4 using DEM simulation. They examined the effect of particle properties such as size, shape and friction by the simulated force and torque on the impeller blade in the particle bed.…”

Section: Powder Flow By Mechanical Forcementioning

confidence: 99%

See 1 more Smart Citation

A Review: Recent Progress on Evaluation of Flowability and Floodability of Powder

Ogata

2019

KONA

View full text Add to dashboard Cite

Recent studies evaluating the flowability and floodability of cohesive powder under conditions of consolidation, mechanical force, vibrating force, fluid force, and floodability are reviewed. The ball indentation test is an effective method for evaluating the flowability of a small amount of cohesive powder at very low stress under consolidation conditions. The environmental conditions such as temperature and humidity play an important role in the flow of cohesive powder. With regard to cohesive powder flowing under mechanical force, the FT4 powder rheometer can evaluate the powder flowability using the total energy which is related to the shear stress on the impeller blade. The vibrating capillary method and the vibrating shear tube method are effective for the measurement of the flowability of strongly cohesive powder. The test using powder discharge by air flow can assess the flowability of cohesive powder which Carr's flowability index is an equivalent level by using mass flow rate and interstitial air pressure. Finally, the flushing of cohesive powder occurs when the interstitial air pressure and the void fraction are high. The pressure difference between the interstitial air pressure and the outside of an orifice are the dominant factors in the spouting of powder.

show abstract

Section: Powder Flow By Mechanical Forcesupporting

confidence: 70%

Section: Powder Flow By Mechanical Forcementioning

confidence: 99%

A Review: Recent Progress on Evaluation of Flowability and Floodability of Powder

Ogata

2019

KONA

View full text Add to dashboard Cite

show abstract

“…It was observed that the flow energy could decrease to 12 mJ if the particle-particle friction coefficient was set to zero. Bharadwaj et al (2010) and Hare et al (2015) also showed that the flow energy was sensitive to the interparticle friction coefficient. Hence, to get a better agreement, it is possible to fine-tune the friction coefficients so that the flow energy is the same in both experimental work and numerical simulation.…”

Section: Snapshotsmentioning

confidence: 99%

“…Recently, several studies have focused on the analysis of the powder mechanics of FT4 by numerical simulations. Bharadwaj et al (2010) used the Discrete Element Method (DEM) to simulate the effect of friction coefficient and particle shape on the resistance force and torque of the blade in FT4, and showed that the flow energy was sensitive to the particle shape and friction coefficients. However, the strain rate and the stress within the bed during the test in FT4 have not been well characterised.…”

Section: Introductionmentioning

confidence: 99%

Analysis of powder rheometry of FT4: Effect of air flow

Nan

Ghadiri

Wang

2017

Chemical Engineering Science

View full text Add to dashboard Cite

Understanding of particle flow behaviour as a function of strain rate is of great interest in many items of equipment of industrial processes, such as screw conveyors, impeller mixers, and feeders, etc. The traditional commercial instruments for bulk powder flow characterisation, such as shear cells, operate at low shear strain rates, and are not representative of unit operations under dynamic conditions. In recent years, the FT4 powder rheometer of Freeman Technology has emerged as a widely used technique for characterising particle flow under dynamic conditions of shear strain rate; yet little is known about its underlying powder mechanics. We analyse the effect of gas flow on the flow behaviour of cohesionless particles in FT4 both experimentally and by numerical simulations using the combined discrete element method (DEM) and computational fluid dynamics (CFD). The results show that the effect of gas flow on the flow energy could be described by the resultant fluid-induced drag on the particles above the blade position as the impeller penetrates the bed. The strain rate in front of the blade is mainly determined by the impeller tip speed, and is not sensitive to the gas flow and particle size. The flow energy correlates well with the shear stress in front of the blade. They both increase with the strain rate and are significantly reduced by the upward gas flow.

show abstract

“…In previous studies default CoR values of EDEM™ software (0.5) were used (12,27 (29). For different kinds of coated tablets they found CoR values that ranged from 0.4 to 0.9 (30).…”

Section: Coefficient Of Restitutionmentioning

confidence: 99%

Experimental Analysis of Tablet Properties for Discrete Element Modeling of an Active Coating Process

et al. 2013

View full text Add to dashboard Cite

Abstract. Coating of solid dosage forms is an important unit operation in the pharmaceutical industry. In recent years, numerical simulations of drug manufacturing processes have been gaining interest as process analytical technology tools. The discrete element method (DEM) in particular is suitable to model tabletcoating processes. For the development of accurate simulations, information on the material properties of the tablets is required. In this study, the mechanical parameters Young's modulus, coefficient of restitution (CoR), and coefficients of friction (CoF) of gastrointestinal therapeutic systems (GITS) and of activecoated GITS were measured experimentally. The dynamic angle of repose of these tablets in a drum coater was investigated to revise the CoF. The resulting values were used as input data in DEM simulations to compare simulation and experiment. A mean value of Young's modulus of 31.9 MPa was determined by the uniaxial compression test. The CoR was found to be 0.78. For both tablet-steel and tablet-tablet friction, active-coated GITS showed a higher CoF compared with GITS. According to the values of the dynamic angle of repose, the CoF was adjusted to obtain consistent tablet motion in the simulation and in the experiment. On the basis of this experimental characterization, mechanical parameters are integrated into DEM simulation programs to perform numerical analysis of coating processes.

show abstract

Discrete element simulation study of a Freeman powder rheometer

Cited by 99 publications

References 39 publications

A Review: Recent Progress on Evaluation of Flowability and Floodability of Powder

A Review: Recent Progress on Evaluation of Flowability and Floodability of Powder

Analysis of powder rheometry of FT4: Effect of air flow

Experimental Analysis of Tablet Properties for Discrete Element Modeling of an Active Coating Process

Contact Info

Product

Resources

About