Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
In the present study, laser-induced fluorescence (LIF) is used to investigate the mixing process of a droplet impacting onto a thin liquid film. A robust multidimensional calibration procedure is developed enabling the extraction of local instantaneous dye concentrations as well as film heights. A series of validation measurements are conducted confirming a low reconstruction error of $$4.53\%$$ 4.53 % . The impact-induced mixing process is thoroughly investigated across various liquid film thicknesses to examine the propagation of the mixing zone and the instantaneous radial concentration gradients within it. It is shown that the maximum extent of the mixing zone scales inversely proportional with the thickness of the liquid film. Within our experiments, we discover the formation of wall-induced vortex ring instabilities subsequent to impact. The disintegration of vortex rings during droplet impact significantly enhances convection-driven mixing, as quantified by the coefficient of variation. Graphical abstract
In the present study, laser-induced fluorescence (LIF) is used to investigate the mixing process of a droplet impacting onto a thin liquid film. A robust multidimensional calibration procedure is developed enabling the extraction of local instantaneous dye concentrations as well as film heights. A series of validation measurements are conducted confirming a low reconstruction error of $$4.53\%$$ 4.53 % . The impact-induced mixing process is thoroughly investigated across various liquid film thicknesses to examine the propagation of the mixing zone and the instantaneous radial concentration gradients within it. It is shown that the maximum extent of the mixing zone scales inversely proportional with the thickness of the liquid film. Within our experiments, we discover the formation of wall-induced vortex ring instabilities subsequent to impact. The disintegration of vortex rings during droplet impact significantly enhances convection-driven mixing, as quantified by the coefficient of variation. Graphical abstract
Inertia-dominated droplet impact transfers momentum to a dry flat target within a short span of time t characterized by (droplet diameter D)/(impact speed U). We investigate experimentally how impact force dynamics change when a droplet hits a thin liquid film of thickness H, less than or approximately equal to the droplet diameter, atop the flat target. Impact force and morphology are recorded simultaneously by piezoelectric force sensing and high-speed video imaging. Compared with a dry surface, the force of droplet impact on a thin liquid film is found to follow the same initial [Formula: see text] scaling and reach a slightly higher peak value, but at a significantly later time. Modeling the impact process as a perfect inelastic collision between the droplet and a liquid column of height equal to the film thickness yields the proper timescale [Formula: see text] to characterize temporal evolution of the impact force near the inertial peak and through its subsequent exponential decay. The impact crater penetration depth developing within the thin film over the same time span is also found to collapse to a self-similar form based on this characteristic timescale, which attests to the validity of the inelastic collision model in capturing the underlying impact flow physics.
The fouling of aero-engine blades is the main cause of degradation of engine performance and online washing is one of the most effective methods for restoring engine performance. The flow characteristics of the washing fluid after it impinges on the blade surface are critical to the process. The liquid film flow becomes complicated after being impacted by a droplet, because the fouling blade is a random rough surface. The purpose of this study is to evaluate the dynamical characteristics of droplets after they impact the liquid film, focusing on the diameter, the height of the coronal water bloom, and the near-wall flow. We establish a random rough surface to simulate the droplet impacting the liquid film on the fouling surface and analyze the morphological evolution of the corona during the droplet impact process. The results show that an increase in the particle size has a greater impact on the coronal diameter than the coronal height. In addition, a higher droplet impact velocity and thicker liquid film are conducive to the secondary atomization of droplets and improve the transport rate of the cleaning solution. However, the flowability of the liquid film at the impact point is best when the droplet impacts the thin liquid film. Increasing the thickness of the liquid film gradually helps to improve its overall fluidity and results in a better cleaning effect.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.