Removing Gas from a Closed-End Small Hole by Irradiating Acoustic Waves with Two Frequencies

Filling microstructures in the air with liquid or removing trapped gases from a surface in a liquid are required in processes such as cleaning, bonding, and painting. However, it is difficult to deform the gas–liquid interface to fill a small hole with liquid when surface tension has closed one end. Therefore, it is necessary to have an efficient method of removing gas from closed-end holes in liquids. Here, we demonstrate the gas-removing method using acoustic waves from small holes. We observed gas column oscillation by changing the hole size, wettability, and liquid surface tension to clarify the mechanism. First, we found that combining two different frequencies enabled complete gas removal in water within 2 s. From high-speed observation, about half of the removal was dominated by droplet or film formation caused by oscillating the gas column. The other half was dominated by approaching and coalescing the divided gas column. We conclude that the natural frequency of both the air column and the bubbles inside the tube are important.

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Effect of liquid surface tension on small hole distillation sieve tray pressure drop

AIChE Journal ◽

10.1002/aic.690410409 ◽

1995 ◽

Vol 41 (4) ◽

pp. 819-827 ◽

Cited By ~ 3

Author(s):

Michael W. Biddulph ◽

Christopher P. Thomas

Keyword(s):

Surface Tension ◽

Pressure Drop ◽

Liquid Surface ◽

Small Hole ◽

Sieve Tray ◽

Liquid Surface Tension

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Investigation of Flow Pattern and Void Fraction of Air and Low Surface Tension Liquid in A 30° Inclined Small Pipe

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences ◽

10.37934/arfmts.83.2.7383 ◽

2021 ◽

Vol 83 (2) ◽

pp. 73-83

Author(s):

Sudarja ◽

Sukamta ◽

Fauzan Saputra

Keyword(s):

Surface Tension ◽

Flow Pattern ◽

Test Section ◽

High Speed ◽

Liquid Surface ◽

Phase Flow ◽

Distilled Water ◽

Two Phase ◽

Liquid Surface Tension ◽

Churn Flow

Two-phase flow in the mini pipe is applied in wide fields. The most common of two-phase flow is a couple of gas and liquid. The essential properties of the liquid are density, viscosity, and surface tension. There are many variations of the flow direction, horizontal, incline, and vertical, in terms of orientation. The two-phase investigation of flow pattern and void fraction of air and low surface tension liquid in a 30° inclined small pipe has been carried out. Dry air was used as a gas phase, while the liquid was the mixture solution of distilled water and 3% (by volume) of butanol. Butanol addition aimed to decrease the surface tension, which became 42.9 millinewton/meter, instead of 71 mN/m when using distilled water. The test section was a 130 mm length, 1.6 mm inner diameter circular glass pipe. The rig used was equipped with the air compressor, pressure tank, high-speed camera, liquid flow meter, and gas flow meter. The liquid was fed to the test section by the pressurized tank, instead of directly pumped, to avoid pulsation. Ranges of gas and liquid superficial velocities were 0.025 – 66.3 m/s and 0.033 – 4,935 m/s, respectively. Flow patterns were obtained from the captured high-speed video. Meanwhile, the void fractions were acquired by image processing of the video. As a result, five distinctive flow patterns were observed: plug, slug-annular, churn, bubbly, and annular. The separated flow was absent. The change of the liquid surface tension affected the shifting of some transition boundary lines in the flow pattern map. The transition line between slug-annular and annular against churn flow was shifted to the lower side or toward lower JL when the liquid surface tension decreased. In short, the churn flow was easier to be formed when the liquid surface tension was lower.

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Trickle/pulse flow regime transition in downflow packed tower involving foaming liquids

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq111201011s ◽

2012 ◽

Vol 18 (3) ◽

pp. 349-359

Author(s):

Vijay Sodhi

Keyword(s):

Surface Tension ◽

Liquid Flow ◽

Liquid Surface ◽

Regime Transition ◽

Pulse Flow ◽

Packed Tower ◽

Flow Rates ◽

Transition Boundary ◽

Liquid Surface Tension ◽

Pulsing Flow

The most of past studies in foaming trickle bed reactors aimed at the improvement of efficiency and operational parameters leads to high economic advantages. Conventionally most of the industries rely on frequently used gas continuous flow (GCF) where operational output is satisfactory but not yields efficiently as in pulsing flow (PF) and foaming pulsing flow (FPF). Hydrodynamic characteristics like regime transitions are significantly influenced by foaming nature of liquid as well as gas and liquid flow rates. This study?s aim was to demonstrate experimentally the effects of liquid flow rate, gas flow rates and liquid surface tension on regime transition. These parameters were analyzed for the air-aqueous Sodium Lauryl Sulphate and air-water systems. More than 240 experiments were done to obtain the transition boundary for trickle flow (GCF) to foaming pulsing flow (PF/FPF) by use excessive foaming 15-60 ppm surfactant compositions. The trickle to pulse flow transition appeared at lower gas and liquid flow rates with decrease in liquid surface tension. All experimental data had been collected and drawn in the form of four different transitional plots which are compared and drawn by using flow coordinates proposed by different researchers. A prominent decrease in dynamic liquid saturation was observed especially during regime transitional change. The reactor two phase pressure evident a sharp rise to verify the regime transition shift from GCF to PF/FPF. Present study reveals, the regime transition boundary significantly influenced by any change in hydrodynamic as well as physiochemical properties including surface tension.

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