A Numerical Investigation on the Collision Behavior of Polymer Droplets

Qian, Lijuan; Cong, Hongchuan; Zhu, Chenlin

doi:10.3390/polym12020263

Cited by 13 publications

(5 citation statements)

References 31 publications

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“…The numerical resolution related to the cell refinement level of the droplet is computed as D 0 /Δ x , where D 0 is the initial diameter of the droplet. The numerical simulation method and the grid independence are verified by Qian et al [ 23 ].…”

Section: Numerical Frameworkmentioning

confidence: 97%

A Numerical Investigation on the Collision Behavior of Unequal-Sized Micro-Nano Droplets

et al. 2020

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Micro-nano droplet collisions are fundamental phenomena in the applications of nanocoating, nano spray, and microfluidics. Detailed investigations of the process of the droplet collisions under higher Weber are still lacking when compared with previous research studies under a low Weber number below 120. Collision dynamics of unequal-sized micro-nano droplets are simulated by a coupled level-set and volume of fluid (CLSVOF) method with adaptive mesh refinement (AMR). The effects of the size ratio (from 0.25 to 0.75) and different initial collision velocities on the head-on collision process of two unequal-sized droplets at We = 210 are studied. Complex droplets will form the filament structure and break up with satellite droplets under higher Weber. The filament structure is easier to disengage from the complex droplet as the size ratio increases. The surface energy converting from kinetic energy increases with the size ratio, which promotes a better spreading effect. When two droplets keep the constant relative velocity, the motion tendency of the droplets after the collision is mainly dominated by the large droplet. On one hand, compared with binary equal-sized droplet collisions, a hole-like structure can be observed more clearly since the initial velocity of a large droplet decreases in the deformation process of binary unequal-sized droplets. On the other hand, the rim spreads outward as the initial velocity of the larger droplet increases, which leads to its thickening.

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Section: Numerical Frameworkmentioning

confidence: 97%

A Numerical Investigation on the Collision Behavior of Unequal-Sized Micro-Nano Droplets

et al. 2020

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“…Existing research, including binary droplet collisions in free space , and collisions between the falling droplet and sessile droplet on the substrate, , mainly focused on falling droplets. Since the conditions encountered in the ADE system are notably different from those in the studies on falling droplets (e.g., the droplet generation methods, the droplet diameter and velocity, and the droplet flying direction), the earlier results could not be directly applied to collision behavior studies of acoustically excited droplets.…”

Section: Introductionmentioning

confidence: 99%

Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Guo

Zhang

et al. 2023

Langmuir

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Acoustic droplet ejection (ADE) is a noncontact technique for micro-liquid handling (usually nanoliters or picoliters) that is not restricted by nozzles and enables high-throughput liquid dispensing without sacrificing precision. It is widely regarded as the most advanced solution for liquid handling in large-scale drug screening. Stable coalescence of the acoustically excited droplets on the target substrate is a fundamental requirement during the application of the ADE system. However, it is challenging to investigate the collision behavior of nanoliter droplets flying upward during the ADE. In particular, the dependence of the droplet's collision behavior on substrate wettability and droplet velocity has yet to be thoroughly analyzed. In this paper, the kinetic processes of binary droplet collisions were investigated experimentally for different wettability substrate surfaces. Four states occur as the droplet collision velocity increases: coalescence after minor deformation, complete rebound, coalescence during rebound, and direct coalescence. For the hydrophilic substrate, there are wider ranges of Weber number (We) and Reynolds number (Re) in the complete rebound state. And with the decrease of the substrate wettability, the critical Weber and Reynolds numbers for the coalescence during rebound and the direct coalescence decrease. It is further revealed that the hydrophilic substrate is susceptible to droplet rebound because the sessile droplet has a larger radius of curvature and the viscous energy dissipation is greater. Besides, the prediction model of the maximum spreading diameter was established by modifying the droplet morphology in the complete rebound state. It is found that, under the same Weber and Reynolds numbers, droplet collisions on the hydrophilic substrate achieve a smaller maximum spreading coefficient and greater viscous energy dissipation, so the hydrophilic substrate is prone to droplet bounce.

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“…Numerical simulations have been extensively used to investigate nasal spray deliveries [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Kimbell et al [ 26 ] simulated the deposition fractions of 20 and 50 μm droplets in an MRI-based nasal airway model with an inhalation rate of 15 L/min and predicted more than 90% of droplets being deposited in the anterior nose.…”

Section: Introductionmentioning

confidence: 99%

Liquid Film Translocation Significantly Enhances Nasal Spray Delivery to Olfactory Region: A Numerical Simulation Study

April

Sami

2021

Pharmaceutics

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Previous in vivo and ex vivo studies have tested nasal sprays with varying head positions to enhance the olfactory delivery; however, such studies often suffered from a lack of quantitative dosimetry in the target region, which relied on the observer’s subjective perception of color changes in the endoscopy images. The objective of this study is to test the feasibility of gravitationally driven droplet translocation numerically to enhance the nasal spray dosages in the olfactory region and quantify the intranasal dose distribution in the regions of interest. A computational nasal spray testing platform was developed that included a nasal spray releasing model, an airflow-droplet transport model, and an Eulerian wall film formation/translocation model. The effects of both device-related and administration-related variables on the initial olfactory deposition were studied, including droplet size, velocity, plume angle, spray release position, and orientation. The liquid film formation and translocation after nasal spray applications were simulated for both a standard and a newly proposed delivery system. Results show that the initial droplet deposition in the olfactory region is highly sensitive to the spray plume angle. For the given nasal cavity with a vertex-to-floor head position, a plume angle of 10° with a device orientation of 45° to the nostril delivered the optimal dose to the olfactory region. Liquid wall film translocation enhanced the olfactory dosage by ninefold, compared to the initial olfactory dose, for both the baseline and optimized delivery systems. The optimized delivery system delivered 6.2% of applied sprays to the olfactory region and significantly reduced drug losses in the vestibule. Rheological properties of spray formulations can be explored to harness further the benefits of liquid film translocation in targeted intranasal deliveries.

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A Numerical Investigation on the Collision Behavior of Polymer Droplets

Cited by 13 publications

References 31 publications

A Numerical Investigation on the Collision Behavior of Unequal-Sized Micro-Nano Droplets

A Numerical Investigation on the Collision Behavior of Unequal-Sized Micro-Nano Droplets

Effect of Wettability on the Collision Behavior of Acoustically Excited Droplets

Liquid Film Translocation Significantly Enhances Nasal Spray Delivery to Olfactory Region: A Numerical Simulation Study

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