Large-scale SPH simulations of droplet impact onto a liquid surface up to the consequent formation of Worthington jet

The fluid physics of splashing, spreading, and dispersion of a large-scale water droplet is investigated both experimentally and with model simulation. Several new phenomena of the droplet impact beyond conventional Rayleigh-Taylor instability theory are reported. First, our experimental data show that the number of fingers or instabilities along the spreading rim cannot be predicted by Allen's (1975) Rayleigh-Taylor equation. Second, we report that the surrounding medium (air) along with impact angle and droplet shape upon impact affect ejection velocity and splashing. Finally, the fundamental instability of the finger formation along the spreading rim may be due to interactions initiated by the compressed and displaced air, rather than the spreading of the liquid decelerating through the air. Several important correlations between the droplet impact velocities, the amount of spray ejected, the spray ejection speed, and the number of fingers or instabilities are presented.

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Experimental study on the effect of the liquid/surface thermal properties on droplet impact

Thermal Science ◽

10.2298/tsci190905142l ◽

2020 ◽

pp. 142-142

Author(s):

Omar Lamini ◽

Rui Wu ◽

Changying Zhao

Keyword(s):

Thermal Properties ◽

Impact Velocity ◽

Thermophysical Properties ◽

Liquid Surface ◽

Droplet Impact ◽

Surface Type ◽

Droplet Dynamics ◽

Stainless Steel 304 ◽

Leidenfrost Temperature ◽

Droplet Liquid

Droplet impact on hot surfaces is widely encountered in industry and engineering applications. In the present paper we investigate the effect of the combination of the droplet liquid type and the solid surface type and their effect on droplet impact dynamics. We test three surfaces, copper 110, aluminum 1199 and stainless steel 304, and two liquids, water and ethanol. These surfaces and liquids are characterized by high and low thermophysical properties. The three surfaces are tested with water to investigate the effect of the surface on the droplet dynamics. After that, we test both liquids with aluminum. Our findings showed that the Leidenfrost temperature does not always correlate with the surface thermal properties as reported in the literature. Some surfaces can undergo changes because of the heating and this reduces their initial thermal properties. For this reason, such surfaces are capable to show two Leidenfrost temperatures because of the thermophysical properties reduction during heating. Our findings also revealed that the Leidenfrost temperature of liquids with low thermophysical properties including surface tension, evaporation latent heat and density show trivial effect by the droplet impact velocity; i.e. the Leidenfrost temperature show trivial increase by increasing the droplet impact velocity. Liquids with high thermophysical properties show significant Leidenfrost temperature increase by increasing the impacting velocity.

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Using Ultrasonic Sensors to Develop a Wireless Level Control in Reservoirs with Liquid Chemical Products

Revista de Chimie ◽

10.37358/rc.19.2.6918 ◽

2019 ◽

Vol 70 (2) ◽

pp. 365-372 ◽

Cited By ~ 1

Author(s):

Gabriela Bucur ◽

Adrian-George Moise ◽

Cristina Popescu

Keyword(s):

Pid Controller ◽

Large Scale ◽

Liquid Surface ◽

Level Control ◽

New Class ◽

Level Sensor ◽

Liquid Chemical ◽

Chemical Products ◽

Level Monitoring

The purpose of this paper is to show the research results for improving the quality of a level control system by using an ultrasonic level sensor. By using an ultrasonic sensor in a liquid level control loop, the authors wanted to experiment the use of this new class of sensors, which are working without contact with the liquid surface or volume. In industry, using this type of transducer is becoming more and more useful, having large scale applications, from dangerous liquids reservoirs level monitoring, to waste water level monitoring in treatment plants, and to level control systems for a wide class chemical products. The research also demonstrated the efficiency of the system remote control by using a dual-loop PID controller.

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Numerical simulation of droplet impact on solid or liquid surface

The Proceedings of Ibaraki District Conference ◽

10.1299/jsmeibaraki.2020.28.111 ◽

2020 ◽

Vol 2020.28 (0) ◽

pp. 111

Author(s):

Masatoshi WATANABE ◽

Hayato TERAISHI ◽

Taito KOEDA ◽

Yoshiaki HANEDA

Keyword(s):

Numerical Simulation ◽

Liquid Surface ◽

Droplet Impact

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Formation and rupture of gas film of antibubble

Technical Sciences ◽

10.31648/ts.5376 ◽

2020 ◽

Vol 23 (1) ◽

pp. 91-104

Author(s):

Lichun Bai ◽

Jinguang Sun ◽

Zhijie Zeng ◽

Yuhang Ma ◽

Lixin Bai

Keyword(s):

Liquid Film ◽

High Speed ◽

Liquid Surface ◽

Single Layer ◽

Liquid Films ◽

Droplet Impact ◽

Liquid Interface ◽

High Speed Photography ◽

Merging Process ◽

The Impact

The formation and rupture of gas film in the process of formation, rupture and coalescence of antibubbles were investigated by high-speed photography. It was found that a gas film will appear and wrap a droplet when the droplet hit a layer of liquid film or foam before impacting the gas-liquid interface. The gas film may survive the impact on the gas-liquid interface and act as the gas film of an antibubble. A multilayer droplet will be formed when the droplet hits through several layer of liquid films, and a multilayer antibubble will be formed when the multilayer droplet impact a gas-liquid interface or a single layer of foam on the liquid surface. The way to generate antibubbles by liquid films will undergo the formation and rupture of gas films. The coalescence of two antibubbles, which shows a similar merging process of soap bubbles, also undergo the rupture and formation of gas films. The rupture of gas film of antibubble caused by aging and impact is also discussed.

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