Solids motion in a conical frustum-shaped high shear mixer granulator

Ng, Boonho; Kwan, C.C.; Ding, Yulong; Ghadiri, Mojtaba; Fan, Xianfeng

doi:10.1016/j.ces.2006.10.003

Cited by 19 publications

(23 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The trend of the variation of strength for different scales using the constant Froude number is surprising, as it is intuitively expected that the 5 L scale should produce stronger granules as compared to the 1 L scale. This point was investigated by identifying the velocity field in the Cyclomix [38][39] . It was found that under a constant Froude number, the velocity gradient in the 1 L is higher than the 5 L scale.…”

Section: Single Particle Crushingmentioning

confidence: 99%

Scale-up of High-Shear Mixer Granulators

Rahmanian

Hassanpour

et al. 2008

KONA

View full text Add to dashboard Cite

show abstract

Section: Single Particle Crushingmentioning

confidence: 99%

Scale-up of High-Shear Mixer Granulators

Rahmanian

Hassanpour

et al. 2008

KONA

View full text Add to dashboard Cite

show abstract

“…6.2a). Several studies have described two distinct flow regions in mixers with rotating impellers: a high particle speed region close to the impeller and a low particle speed region elsewhere (Stewart et al, 2001a, Ng et al, 2007a. PEPT measurements have shown that the particle velocity was two time greater near the impeller than in the rest of the powder bed (Tran et al, 2005).…”

Section: Two-compartment Model (Two-cm)mentioning

confidence: 99%

“…More complex mixers include multi-impeller mixers such as the cyclomix in which the flow is observed to move either up or down the wall depending on the impeller locations (Ng et al, 2007a). Impeller design also has significant impact on the flow with the planetary mixer "K-beater" producing highly complex flow patterns (Hiseman et al, 2002).…”

Section: Impeller and Mixer Designmentioning

confidence: 99%

“…Work on understanding powder flow has mainly focussed on industrial vHSM with rotating impellers at the base e.g. Fielder, Diosna, Collette Gral, Niro Pellmix (Knight et al, 2000, Schaefer et al, 1993, though other studies also include the cyclomix (Ng et al, 2007a,b, Hassanpour et al, 2009) and planetary mixer (Hiseman et al, 2002) (see Figure 1.5). A number of researchers have designed custom mixers in order to simplify complex flow , Plank et al, 2003, c) Niro Pellmix (Knight et al, 2000, Schaefer et al, 1993, d) Collette Gral (Faure et al, 1999), e) Zanchetta (Nilpawar et al, 2006), f) custom design vHSM (Tu et al, 2009, Knight et al, 2001, Bridson et al, 2007, g) planetary mixer (Hiseman et al, 2002), and h) cyclomix mixer granulator (Ng et al, 2007a) Knight et al (2000) patterns (see Figure 1.6).…”

Section: Granulation Equipmentmentioning

confidence: 99%

“…. , Plank et al, 2003, c) Niro Pellmix (Knight et al, 2000, Schaefer et al, 1993, d) Collette Gral (Faure et al, 1999), e) Zanchetta (Nilpawar et al, 2006), f) custom design vHSM (Tu et al, 2009, Knight et al, 2001, Bridson et al, 2007, g) planetary mixer (Hiseman et al, 2002), and h) cyclomix mixer granulator (Ng et al, 2007a) 6.1 Properties of each compartment from experimental PEPT data for the two-CM and multi-CM: occupied volume vol, occupancy occ, average particle velocity v p , average dimensionless particle velocity v …”

Section: Granulation Processes As Classified Bymentioning

confidence: 99%

See 2 more Smart Citations

Powder flow in vertical high shear mixer granulators

Tran¹

View full text Add to dashboard Cite

An integral component in understanding the fundamental mechanisms of granulation is the powder flow behaviour within mixer granulators. All three classes of granulation rate processes: wetting and nucleation, consolidation and coalescence, and attrition and breakage require detailed knowledge of flow fields in mixing systems to enable rational approaches to the prediction of granule attributes. The three objectives of this thesis are to 1) develop a powder flow regime map to characterise the powder flow field, 2) investigate the effect of impeller speed, powder cohesion and blade-rake angle on powder flow and mixing behaviour and, 3) outline a framework for compartment models of vertical-axis high shear mixer (vHSM) granulators.In the development of the powder flow regime map, two distinct regimes were identified. Ideal roping regime occurs at high impeller speeds when the rotating blades pushes the powder out and up the mixer wall, and then back down the free surface forming the "roping" flow pattern. This stable flow behaviour promotes high vertical bed turnover which is essential for controlled granulation. In this regime, the powder in the blade region has sufficient rotational inertia to overcome gravitational forces (i.e. powder Froude number greater than unity). If this criterion is not met, the mixing system remains in the undesirable bumping regime. This regime is characterised by poor bed turnover and non-uniform shear distribution within the powder bed. In the bumping regime, multiple transitional states are observed with increasing impeller speeds for this particular system, which has not been fully characterised in the literature before. An explanation for the observed apparent roping behaviour based on bed resonance is given. These intermediary transitional states can be differentiated by blade-powder interactions.From these observations, a powder flow regime map for vertical-axis mixer granulators is proposed based on two dimensionless groups: powder Froude number, the ratio of the powder rotational inertial to gravitational forces and the Bed Resonance number, which characterises the interaction of the bulk motion of the powder bed with the passage of impeller blades beneath it. The regime map was validated by experimental results utilising ii iii the well-established, non-invasive tracking technique of Positron Emission Particle Tracking (PEPT) and torque measurements.Investigations into the effect of impeller speed, powder cohesion and blade-rake angle on powder flow and mixing behaviour were conducted using PEPT. Results showed that powder velocity, bed porosity and shear rates varied spatially within the mixer granulator. Studies of the stable roping regime revealed that the average powder velocity in the impeller zone was 1.66 m/s (≈25% of the impeller tip speed). In comparison, the average powder velocity in the circulation and surface zone was approximately half of the impeller zone at 0.9 and 0.74 m/s, respectively (12% and 11% of the impeller tip speed). With the addition of mois...

show abstract

Discrete Element Method (DEM) Simulation of Powder Mixing Process

Hassanpour

Ghadiri

2015

Pharmaceutical Blending and Mixing

View full text Add to dashboard Cite

Solids motion in a conical frustum-shaped high shear mixer granulator

Cited by 19 publications

References 58 publications

Scale-up of High-Shear Mixer Granulators

Scale-up of High-Shear Mixer Granulators

Powder flow in vertical high shear mixer granulators

Discrete Element Method (DEM) Simulation of Powder Mixing Process

Contact Info

Product

Resources

About