Investigation of the influence of impact velocity and liquid bridge volume on the maximum liquid bridge length

Grohn, Philipp; Oesau, Tobias; Heinrich, Stefan; Antonyuk, Sergiy

doi:10.1016/j.apt.2022.103630

Cited by 4 publications

(8 citation statements)

References 42 publications

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“…A wet contact begins as soon as the liquid layers on the contact partners touch and ends as soon as the maximum liquid bridge length is reached. During this contact time, the capillary and viscous forces must be taken into account [ 8 , 26 ]. In the literature, several models describe the capillary forces for symmetric pendular bridges [ 18 , 23 , 38 , 39 , 40 ] on the basis of the total liquid bridge energy and the pressure difference across the liquid bridge.…”

Section: Model Descriptionmentioning

confidence: 99%

“…This critical distance, also called the maximum liquid bridge length, is described by various models [ 38 , 39 , 42 , 43 , 44 , 45 ]. All models have in common that they do not consider the significant influence of the impact velocity on the bridge length, which was found in our recent experimental study [ 26 ]. In this work, three different experimental setups were developed to investigate the maximum liquid bridge length in a velocity range from 0.0001 s∙m −1 to 4 s∙m −1 for particle–particle as well as particle–wall contact.…”

Section: Model Descriptionmentioning

confidence: 99%

“…Based on our experimental results, we extended the model of Mikami et al [ 39 ] to account for the strong influence of the impact velocity

on the maximum liquid bridge length. For particle–wall contact, the maximum bridge length was expressed as:

where,

represents a constant parameter with was found in [ 26 ] to have a value of 4.424 s∙m −1 . For particle–particle contact, the maximum liquid bridge length was calculated as:

where,

is a constant parameter with the value of 6.266 s∙m −1 .…”

Section: Model Descriptionmentioning

confidence: 99%

“…The particulate phase was calculated with DEM using the open-source software LIGGGHTS ® [ 55 ] and coupled with the CFD by the open-source software CFDEM ® coupling [ 29 ]. Similar to previous studies, round particles with a diameter of 2.8 mm consisting of a ceramic core and a shell of polyvinyl butyral (PVB) were investigated [ 5 , 8 , 26 , 56 ]. Initially wetted particles with a total mass of 1 kg were generated above the rotor plate.…”

Section: Simulation Setupmentioning

confidence: 99%

“…In the numerical simulations, the capillary forces due to the presence of liquid on particles were considered based on the model of Israelachvili [ 23 ] and the viscous forces were calculated according to the models of Lian et al [ 24 ] and Popov [ 25 ]. In addition, a new model was implemented to describe the velocity-dependent rupture length of liquid bridges [ 8 , 26 ]. With the improved MPT equipment, the particle dynamics of spherical particles with a minimum diameter of 2.8 mm could be measured.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation of the Particle Dynamics in a Rotorgranulator Depending on the Properties of the Coating Liquid

2023

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In the pharmaceutical industry, the coating of particles is a widely used technique to obtain desired surface modifications of the final product, e.g., controlled release of the active agents. The production of round, coated particles is particularly important, which is why fluidized bed rotor granulators (FBRG) are often used for this process. In this work, Computational Fluid Dynamics (CFD) coupled with the Discrete Element Method (DEM) is used to investigate the wet particle dynamics, depending on the properties of the coating liquid in a FBRG. The DEM contact model was extended by liquid bridge model to account for capillary and viscous forces during wet contact of particles. The influence of the relative contact velocity on the maximum length of the liquid bridge is also considered in the model. Five different cases were compared, in which the particles were initially wetted, and the liquid loading as well as the surface tension and viscosity of the liquid were changed. The results show that increasing viscosity leads to a denser particle bed and a significant decrease in particle rotational velocities and particle motion in the poloidal plane of the FBRG. Reducing the liquid loading and surface tension results in increased particle movement.

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Section: Model Descriptionmentioning

confidence: 99%

Section: Model Descriptionmentioning

confidence: 99%

“…Based on our experimental results, we extended the model of Mikami et al [ 39 ] to account for the strong influence of the impact velocity

on the maximum liquid bridge length. For particle–wall contact, the maximum bridge length was expressed as:

where,

represents a constant parameter with was found in [ 26 ] to have a value of 4.424 s∙m −1 . For particle–particle contact, the maximum liquid bridge length was calculated as:

where,

is a constant parameter with the value of 6.266 s∙m −1 .…”

Section: Model Descriptionmentioning

confidence: 99%