Modelling Deaggregation Due to Normal Carrier–Wall Collision in Dry Powder Inhalers

Alfano, Francesca Orsola; Renzo, Alberto Di; Gaspari, Roberto; Benassi, Andrea; Maio, Francesco Paolo Di

doi:10.3390/pr10081661

Cited by 4 publications

(4 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The DEM simulations were carried out using an in-house customized version of the open-source code MFIX (NETL MFS, Department of Energy (Morgantown, WV, USA), version 18.1.5 [ 46 ]. Johnson-Kendall-Roberts (JKR) model for the cohesive force and constant directional torque (CDT) model for the rolling friction were implemented in the original version of the code (see [ 45 ] for more details). Moreover, a different approach for wall contacts [ 47 ] was preferred to the standard MFIX formulation.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

2023

Self Cite

View full text Add to dashboard Cite

The generation and accumulation of an electrostatic charge from handling pharmaceutical powders is a well-known phenomenon, given the insulating nature of most APIs (Active Pharmaceutical Ingredients) and excipients. In capsule-based DPIs (Dry Powder Inhalers), the formulation is stored in a gelatine capsule placed in the inhaler just before inhalation. The action of capsule filling, as well as tumbling or vibration effects during the capsule life cycle, implies a consistent amount of particle–particle and particle–wall contacts. A significant contact-induced electrostatic charging can then take place, potentially affecting the inhaler’s efficiency. DEM (Discrete Element Method) simulations were performed on a carrier-based DPI formulation (salbutamol–lactose) to evaluate such effects. After performing a comparison with the experimental data on a carrier-only system under similar conditions, a detailed analysis was conducted on two carrier–API configurations with different API loadings per carrier particle. The charge acquired by the two solid phases was tracked in both the initial particle settling and the capsule shaking process. Alternating positive–negative charging was observed. Particle charging was then investigated in relation to the collision statistics, tracking the particle–particle and particle–wall events for the carrier and API. Finally, an analysis of the relative importance of electrostatic, cohesive/adhesive, and inertial forces allowed the importance of each term in determining the trajectory of the powder particles to be estimated.

show abstract

Section: Methodsmentioning

confidence: 99%

“…All the models presented above are described in more detail in Alfano et al [39,45]. The DEM simulations were carried out using an in-house customized version of the open-source code MFIX (NETL MFS, Department of Energy (Morgantown, WV, USA), version 18.1.5 [46].…”

Section: Dem Simulation Techniquementioning

confidence: 99%

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…In industrial environments, the excessive build-up causes unwanted agglomeration and wall-sheeting in the fluidized beds [1][2][3][4][5], pneumatic conveyors [6][7][8][9][10], or during powder handling in general [11]. This is an especially severe problem in the pharmaceutical industry [12][13][14][15] because the formulation of powders is strictly given and often cannot be changed to reduce the charging. Triboelectric charging also plays a vital role in many natural phenomena.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Reynolds number from Re_τ = 150 to 210 on size-dependent bipolar charging

Jantač,

Grosshans

2024

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

We recently found wall-bounded turbulence to suppress and control bipolar triboelectric charging of particles of identical material. This control is due to fluid modifying the motion of light particles. Thus, the particles’ charge distribution depends on their Stokes number distribution. More specifically, fluid forces narrow the bandwidth of the charge distribution, and bipolar charging reduces dramatically. Consequently, not the smallest but mid-sized particles collect the most negative charge. However, the influence of the Reynolds number or particle concentration on bipolar charging of polydisperse particles is unknown. This paper presents the charging simulations of same-material particles the in different wall-bounded flows. In a comprehensive study, we vary the Reynolds number from Reτ = 150 to 210 and the particle number density from 4 × 109m-3 to 1 × 1010m-3 to further explore the influence of the carrier flow on bipolar charging. We model charge transfer based on the balance of transferable charge species. Such species can represent adsorbed ions transferred during collisions or free electrons captured into a lower energy state on the other surface. The turbulent flow is modeled via Direct Numerical Simulations (DNS) and is coupled to the particulate phase modeled via the Discrete Element Method (DEM). Overall, our multiphysics approach couples the fluid dynamics, electric field, triboelectric charging, and particle momentum into one complex simulation.

show abstract

“…The Discrete Element Method (DEM), also in combination with computational fluid dynamics (CFD-DEM), is commonly utilized to model the behavior of granular materials, due to its versatility in dealing with very different flow regimes, packing density and dispersion of particle properties (Golshan et al, 2020;Kieckhefen et al, 2020). DEM has been successfully used to study the segregation of particles differing in size and density in fluidized beds (Di Renzo et al, 2011;Peng et al, 2016), the mixing of electrically charged API and carrier particles for inhalation in a vibrating container (Yang et al, 2015), the mixing of binary particle beds in a rotating drum (Huang and Nakagawa, 2023), the size segregation during powder spreading for additive manufacturing using laser powder bed fusion (Shaheen et al, 2021), the detachment of API from carrier particles in dry powder inhalers (Cui and Sommerfeld, 2015;Tong et al, 2017;Ariane et al, 2018;Alfano et al, 2021a;Alfano et al, 2022a;Alfano et al, 2022b).…”

Section: Introductionmentioning

confidence: 99%

A thick wall concept for robust treatment of contacts in DEM simulation of highly polydisperse particulate systems

Alfano,

Iozzi,

Di Maio

et al. 2024

Front. Chem. Eng.

Self Cite

View full text Add to dashboard Cite

Modelling particulate systems with the Discrete Element Method (DEM) is an established practice, both in the representation and analysis of natural phenomena and in scale-up and optimization of industrial processes. Since the method allows tracking individual particles, each element can possess geometrical, physical, mechanical or chemical surface properties different from those of the other particles. One example is a polydisperse particulate system, i.e., characterized by a size distribution, opposed to the idealized monodisperse case. In conventional DEM, a softer particle stiffness is commonly adopted to reduce the computational time. It might happen that artificially soft particles, when colliding against a wall boundary, exhibit such large, unrealistic overlap that they “pass through” the wall and exit the domain. In the case of highly polydisperse systems, this often occurs when fine particles are pushed against the wall by coarse particles with masses several orders of magnitude larger. In the manuscript, a novel method is proposed, named thick wall, to allow the particles in contact with the walls to experience relatively large overlaps without ending up ejected out the domain. In particular, a careful way to calculate the particle-wall overlap and force unit vector can accommodate normal displacements larger than the maximum usually allowed, i.e., typically the particle radius, thereby preventing particles from being expelled from the domain. First, critical velocities for which single particles and pairs of fine/coarse particle escape the domain are analytically characterized using the linear and the Hertz models. The thick wall concept is then introduced and its effect on the maximum critical velocity is demonstrated with both contact models. Finally, application to pharmaceutical powder composed of carrier (coarse) and active pharmaceutical ingredient (API) (fine) particles in a shaken capsule prove this to be an example of vulnerability to the phenomenon of fine particle ejection and to significantly benefit from the thick wall modification.

show abstract

Modelling Deaggregation Due to Normal Carrier–Wall Collision in Dry Powder Inhalers

Cited by 4 publications

References 35 publications

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

Influence of the Reynolds number from Re_τ = 150 to 210 on size-dependent bipolar charging

A thick wall concept for robust treatment of contacts in DEM simulation of highly polydisperse particulate systems

Contact Info

Product

Resources

About

Modelling Deaggregation Due to Normal Carrier–Wall Collision in Dry Powder Inhalers

Cited by 4 publications

References 35 publications

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

Discrete Element Method Evaluation of Triboelectric Charging Due to Powder Handling in the Capsule of a DPI

Influence of the Reynolds number from Reτ = 150 to 210 on size-dependent bipolar charging

A thick wall concept for robust treatment of contacts in DEM simulation of highly polydisperse particulate systems

Contact Info

Product

Resources

About

Influence of the Reynolds number from Re_τ = 150 to 210 on size-dependent bipolar charging