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1

Perturbations of the depth of liquid penetration into the capillary during bubble departures

Dzienis Paweł

Acta Mechanica et Automatica

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2021

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Vol. 15, no. 4

254--259

EN

In the present paper, the influence of bubble size on liquid penetration into the capillary was experimentally and numerically studied. In the experiment, bubbles were generated from a glass capillary (with an inner diameter equal to 1 mm) in a glass tank containing distilled water, tap water or an aqueous solution of calcium carbonate. These liquids differ in the value of their surface tension, which influences the bubble size. During experimental investigations, air pressure fluctuations in the gas supply system were measured. Simultaneously, the videos showing the liquids’ penetration into the capillary were recorded. Based on the videos, the time series of liquid movements inside the capillary were recovered. The numerical models were used to study the influence of bubble size on the velocity of liquid flow above the capillary and the depth of liquid penetration into the capillary. It was shown that the air volume flow rate and the surface tension have the greatest impact on the changes of pressure during a single cycle of bubble departure (Δp). The changes in pressure during a single cycle of bubble departure determine the depth of liquid penetration into the capillary. Moreover, the values of Δp and, consequently, the depth of liquid penetration can be modified by perturbations in the liquid velocity above the capillary outlet.

2

Study on feature extraction and dynamic properties of bubbles in a liquid-phase flow field

Peng Deqiang, Dong Xianshu, Fan Yuping, Ma Xiaomin

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

268--277

EN

To study the dynamic properties of bubbles generated at different air pressures in a liquid-phase flow field, this paper adopted high-speed camera technology and image processing techniques to extract and calculate the features of bubbles. The results showed that in a deionized water field, the bubbles generated at the air pressure of 0.1 MPa had an average diameter of 4.50 mm, and the bubbles generated at the air pressures of 0.2 MPa and 0.3 MPa had average diameters of 5.74 mm and 5.76 mm respectively; notwithstanding the insignificant differences in average data, the probability distribution of bubble diameter had significant differences with different pressures. During the rise of bubbles, their motion trajectory witnessed an increased amplitude of swing with the increase of air pressure; the bubbles generated at different air pressures did not show any significant differences in rising velocities though.

3

Underwater noise emitted during small-scale air entrainment events

Szuszkiewicz J., Klusek Z.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 1

87--97

EN

The breaking wave phenomenon significantly takes part in the mechanisms of mass, heat and gas exchange at the air-water boundary and depends on the wind velocity. Some of the energy dissipated during this process is converted into underwater sound emitted by oscillating gas bubbles and bubble plumes. However, the underwater noise accompanying the lowest wind speed conditions has received only little attention. This report describes a study aimed at advancing the knowledge of underwater noise emission from air bubbles injected during small-scale breaking events occurring on the water surface. Results of model experiments performed in a small tank are presented. The object of the research is the relationship between the generated noise and the dissipated potential energy of water poured into a tank filled with water of varying physical water properties. Additionally, the impact of various water properties such as salinity, surface tension or microscale gas bubbles was examined. The experiment revealed that noise spectra are affected by different water properties and most likely reffect the varying efficiency of bubble formation and bubble size spectra.

4

The effect of rheology with gas bubbles on linear elastic waves in fluid-saturated granular media

ALI A. A., Strunin D. V.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 3

575--594

EN

Elastic waves in fluid-saturated granular media depend on the grain rheology, which can be complicated by the presence of gas bubbles. We investigated the effect of the bubble dynamics and their role in rheological scheme, on the linear Frenkel-Biot waves of P1 type. For the wave with the bubbles the scheme consists of three segments representing the solid continuum, fluid continuum and bubbles surrounded by the fluid. We derived the Nikolaevskiy-type equation describing the velocity of the solid matrix in the moving reference system. The equation is linearized to yield the decay rate λ as a function of the wave number k. We compared the λ (k) -dependence for the cases with and without the bubbles, using typical values of the input mechanical parameters. For both the cases, the λ(k) curve lies entirely below zero, which implies a global decay of the wave. We found that the increase of the radius of the bubbles leads to a faster decay, while the increase in the number of the bubbles leads to slower decay of the wave.

5

Impact of salinity on the underwater noise generated by small scale air entrainment events

Szuszkiewicz J., Klusek Z., Gorska N.

Hydroacoustics

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2017

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Vol. 20

167--172

EN

Some part of the energy released in the wave breaking process is transformed into the energy of the noise. This sound depends on the water properties, however, there is a lack of reliable data concerning the underwater noise generated by less energetic events. The aim of this study was to understand the impact of salinity on the underwater noise produced during small scale air entrainment events, typical for low wind speed conditions. The tipping trough experiment was performed in a small tank to generate the small scale air injections. Four, linearly placed hydrophones HTI-96-MIN were used to record the acoustic noise accompanying this phenomenon. The bubble plume development, and underwater noise spectra, were compared for salty and fresh water. The potential energy of the modeled events resulted in different spectra, and salinity played an essential role in the emitted underwater noise.

6

Heat load and deuterium plasma effects on SPS and WSP tungsten

Vilémová M., Matějíček J., Nevrlá B., Chernyshova M., Gasior P., Kowalska-Strzeciwilk E., Jäger A.

Nukleonika

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2015

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Vol. 60, No. 2

275--283

EN

Tungsten is a prime choice for armor material in future nuclear fusion devices. For the realization of fusion, it is necessary to address issues related to the plasma–armor interactions. In this work, several types of tungsten material were studied, i.e. tungsten prepared by spark plasma sintering (SPS) and by water stabilized plasma spraying (WSP) technique. An intended surface porosity was created in the samples to model hydrogen/ helium bubbles. The samples were subjected to a laser heat loading and a radiation loading of deuterium plasma to simulate edge plasma conditions of a nuclear fusion device (power density of 108 W/cm2 and 107 W/cm2, respectively, in the pulse intervals up to 200 ns). Thermally induced changes in the morphology and the damage to the studied surfaces are described. Possible consequences for the fusion device operation are pointed out.

7

Pomiar chaotycznego tworzenia się pęcherzyków gazu z zastosowaniem programu LabVIEW

Podgórni E., Rząsa M. R., Ziemnicka E.

Biuletyn Wojskowej Akademii Technicznej

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2014

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Vol. 63, nr 3

115-121

PL

Zjawisko chaosu deterministycznego występuje wskutek zmian parametrów układu. W badaniach poszukiwano bifurkacji - punktów utraty stabilności układu podczas tworzenia się pęcherzyków gazu. Specjalnie utworzone stanowisko połączone z oprogramowaniem LabVIEW pozwalało na mierzenie czasu powstawania pęcherzy przy zmiennym natężeniu objętościowym gazu. Określony został wpływ kształtu oraz średnicy dyszy na osiąganie przez układ stanu chaosu deterministycznego.

EN

The article presents the results of research on the prevalence of deterministic chaos during the formation of gas bubbles. In order to measure the time of the formation of gas bubbles a test bench was built. The research allowed us to determine the bifurcation diagrams for cylindrical and conical nozzles. Bifurcation occurs and it causes that we can see two points for the same gas stream. The system loses stability gradually until the appearance of chaos, i.e., the total instability of the system.

8

The Dynamics of Liquid Movement Inside the Nozzle During the Bubble Departures for Low Air Volume Flow Rate

Dzienis P., Mosdorf R., Wyszkowski T.

Acta Mechanica et Automatica

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2012

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Vol. 6, no. 3

31-36

EN

The main aim of investigation was to analyze the influence of liquid movement inside the nozzle on the dynamics of bubble departure. Dynamics of such process decides about the periodic and aperiodic bubble departures. During the experiment it has been simultaneously recorded: changes of the depth of the nozzle penetration by liquid, air pressure and shape of bubble trajectory directly over the nozzle (in the length of 30 mm). The air volume flow rate was in the range 0.00632 - 0.0381 l/min. There has been shown that for all air volume flow rates the time periods with periodic and aperiodic bubble departures have been occurred. Duration of these intervals varies with the air volume flow rate. It has been found that the aperiodic bubble departures begin when the time of bubble growth increases. The changes of maximum values of liquid position inside the nozzle are associated with changes of the shape of bubble trajectories. There has been shown that straightens of the trajectory precedes the appearance of periodical or aperiodic time period of bubble departures. The aperiodic bubble departures are accompanied by a significant deviation of bubble trajectory from a straight line. The correlation dimension analysis shown that three independent variables are enough to describe the behaviour of liquid movement inside the nozzle. These independent variables may be: liquid velocity, liquid position in the nozzle and gas pressure in the nozzle.

9

Mieszanie dyspersji pęcherzy gazowych w płynie plastycznolepkim

Michajłowski A., Kiljański T.

Inżynieria i Aparatura Chemiczna

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2010

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Nr 4

48-49

PL

Przedstawiono wyniki obserwacji zachowania się pęcherzy gazowych rozproszonych w płynie posiadającym granicę płynięcia w czasie mieszania. Stwierdzono występowanie zjawiska koalescencji pęcherzy z utworzeniem większych, pojedynczych jednostek podążających za łopatkami mieszadła, jak również powstawanie dyspersji licznych drobnych pęcherzyków, które, przy odpowiednio dużej prędkości mieszadła, mogą być na powrót pochłonięte przez większe jednostki.

EN

Investigation results on behavior of gas bubbles dispersed in viscoplastic body during agitating are presented. It was stated that the agitator causes coalescence of small bubbles with the resulting big bubble following the agitator blade. For certain conditions a secondary dispersion of very small bubbles from the big one appeared. At the high enough rotational speed of agitator these bubbles could be again trapped by big bubbles.

10

Frequency and non-linear analysis of bubble paths in bubble chain

Mosdorf R., Wyszkowski T.

Acta Mechanica et Automatica

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2010

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Vol. 4, no. 4

71-77

EN

In the paper the paths of bubbles emitted from the bras nozzle with inner diameter equal to 1.1 mm have been analyzed. The mean frequency of bubble departure was in the range from 1 to 36 Hz. Bubble paths have been recorded using a high speed camera. The image analysis technique has been used to obtain the bubble paths for different mean frequencies of bubble departures. The Fourier, wavelet analysis and recurrence plots have been used to determine the strength of interac- tion between bubbles in column. It has been found that the influence of previously departing bubbles on trajectory of next bubble in the column can be significant for fb > 30 Hz, in this case the bubble paths become less periodic and more instable. In this case the distance between subsequent departing bubbles (S/D) becomes close to 1. It causes that the vertical interaction between departing bubbles is enough strong to change the dynamical properties of bubble paths.

11

Formowanie się kształtów pęcherzy gazowych w płynie plastycznolepkim w początkowym okresie ruchu

Kiljański T., Michajłowski A.

Inżynieria i Aparatura Chemiczna

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2008

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Nr 6

36-37

PL

Przedstawiono wyniki obserwacji kształtowania się pęcherzy gazowych w płynie posiadającym granicę płynięcia w początkowym okresie ruchu w polu sił odśrodkowych. Stwierdzono, że po rozpoczęciu ruchu wirówki pęcherz ulega początkowo znacznemu wydłużeniu, po czym rozpoczyna się jego ruch w kierunku osi obrotów. Większe pęcherze podczas wydłużania dzieliły się na dwa, z których mniejszy pozostawał nieruchomy.

EN

Results of investigations on shaping of gas bubbles in viscoplastic body in the initial phase of movement in centrifugal forces field are presented. It was proved that after the centrifuge was turned on, a bubble considerably elongated before it started to move in the direction of the axis of rotation. Larger bubbles divided into two during the elongation and the smaller of them lasted immobile.

12

Acoustic cavitation and bubble dynamics

Lauterborn W., Kurz T., Mettin R., Koch P., Kröninger D., Schanz D.

Archives of Acoustics

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2008

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Vol. 33, No. 4

609-617

EN

Acoustic cavitation is investigated experimentally and theoretically starting with a single bubble in an acoustic field. The single bubble is trapped in an acoustic resonator and observed by high-speed imaging and acoustic measurements following its transient dynamics to a possible steady state after generation by laser light. Numerical calculations are done to explore the regions of survival for acoustically driven bubbles with respect to dissolution or growth, surface oscillations and positional stability in a standing sound field. The interior gas dynamics is explored via molecular dynamics simulations. A glance is thrown at the complex dynamics of multi-bubble systems.

13

Laser visualization of the flow of bubbles in a pulsed streamer discharge in water

Metel E., Podliński J., Dors M., Mizeraczyk J.

Transactions of the Institute of Fluid-Flow Machinery

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2007

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nr 119

65-78

EN

The pulsed corona discharge in water produces radicals and reactive species, such as O, OH and H202, which can oxidize organic compounds to H20 and CO2. However, the pulsed corona discharge in water generates also shock waves and numerous bubbles, which contains water vapor, oxygen, hydrogen and active species. In this work results of the laser visualization of the gas bubbles flow in a needle-to-cylinder pulsed corona discharge reactor filled with distilled water are presented.

14

Concentration of alfa-terpineol and (2-dodecanoyloxyethyl)trimethyl ammonium bromide required for prevention of air bubble coalescence in aqueous solutions

Szyszka D., Drzymała J., Łuczyński J., Wilk K. A., Patkowski J.

Physicochemical Problems of Mineral Processing

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2006

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Vol. 40

53-59

EN

Flotation is a widely used process in mineral processing. It utilizes different reagents including, collectors and frothers. It was proposed by Cho and Laskowski to use the so-called critical coalescence concentration (CCC) for characterization of flotation frothers. In this paper the CCC values were determined for á-terpineol, which is widely used as a frother in laboratory flotation tests, and for (2-dodecanoyloxyethyl)trimethylammonium bromide (DMM-11) which represents a broad family of reagents known as chemodegradable cationic surfactants. The CCC for α-terpineol was found to be 0.16 mmol/dm3 while for DMM-1, depending of the procedure of approximation, between 0.06 and 0.14 mmol/dm3.

PL

Flotacja jest jednym z najczęściej stosowanych procesów w mineralurgii. Wśród najważniejszych czynników flotacji są reagenty, a w szczególności stosowane odczynniki pianotwórcze (spieniacze). W celu charakteryzowania spieniaczy flotacyjnych Cho i Laskowski wprowadzili pojęcie krytycznego stężenia koalescencji (CCC). W pracy wyznaczano CCC dla typowego spieniacza stosowanego w procesie flotacji, jakim jest .-terpineol oraz dla DMM-11 reprezentującego surfaktanty z grupy chemodegradowalnych estrów kationowych. Stwierdzono, że CCC dla .-terpineolu wynosi 0.16 mmol/dm3, podczas gdy dla DMM-11, w zależności od sposobu aproksymacji, wynosi ono od 0.05 do 0.15 mmol/dm3.

15

Wpływ ścianki naczynia na szybkość pełzającego ruchu pęcherzy gazowych w płynach nienewtonowskich rozrzedzanych ścinaniem

Kiljański T.

Inżynieria i Aparatura Chemiczna

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2006

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Nr 6s

122-123

EN

On the basis of the equation describing wall effect during the motion of a solid sphere in non-Newtonian power—law fluids, an analogical equation was formulated for bubbles and adopted for the motion in a centrifuge taking into consideration bubble size changes during the motion. The experimental verification confirmed the equation validity in the range d/D < 0.2.

16

Ruch pęcherzy gazowych w płynach plastycznolepkich

Kiljański T.

Inżynieria i Aparatura Chemiczna

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2006

|

Nr 6s

120-121

EN

An equation was formulated for the calculation of gas bubble velocity under the centrifugal force in a viscoplastic body described by the Herschel - Bulkley equation. The experimental verification confirmed the validity of the equation but only in a great enough distance from the point where the bubble lasted immobilized despite the buoyancy force.

17

Effect of humic substances and particles on bubble coalescence and foam stability in relation to dissolved air flotation processes

Spyridopoulos M., Simons S., Neethling S., Cilliers J.

Physicochemical Problems of Mineral Processing

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2004

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Vol. 38

37-52

EN

In this paper the effect of humic substances (natural surfactants), electrolytes and solid particles on bubble coalescence, and as a consequence on froth stability, have been investigated. We formed two bubbles of equal size and forced them to collide using a novel experimental apparatus. The interactions were recorded by a high-speed camera, the images of which helped to determine the coalescence frequency and the coalescence time, as well as the mechanisms of the interactions. Two types of humic substances were used, along with three different electrolytes. Humic substances appeared to have a considerable effect on bubble coalescence, while the effect of electrolytes was minimal. Moderate and high hydrophobic glass spheres were used between two bubbles. Very hydrophobic spheres promoted fast bubble coalescence, while moderate hydrophobic spheres had no effect. We present data of coalescence frequency and time, as well as images of the coalescence events. The coalescence frequency was used to validate a parameter, Pf, known as the film failure frequency, used in a simulation model to predict foam height in a gas-sparged vessel. Predictions determined using Pf were then validated by experimentation.

PL

W pracy przeprowadzono badania nad wpływem substancji humusowych (naturalne surfaktanty), elektrolitów i cząstek ciała stałego na koalescencję pęcherzyków powietrza, a w konsekwencji na stabilność piany. Nowa aparatura została wykorzystana do pomiarów sił oddziaływań między dwoma pęcherzykami o jednakowym kształcie. Oddziaływania zostały zarejestrowane przez specjalną kamerę. Obrazy z kamery pozwoliły określić częstotliwość i czas koalescencji, jak również mechanizmy oddziaływania. Dwa rodzaje substancji humusowych użyto do badań oraz trzy rodzaje elektrolitów. Okazało się, że substancje humusowe miały istotny wpływ na koalescencje pęcherzyków. Wpływ elektrolitów był minimalny. Kule szklane o średnim i wysokim stopniu hydrofobowości powierzchni były umieszczane między pęcherzykami. Kule o dużej hydrfobowości powierzchni powodowały szybszą koalescencję pęcherzyków, podczas gdy, kule o średniej hydrofobowości powierzchni nie wykazywały tego efektu. W pracy przedstawiono dane dotyczące częstotliwości koalescencji. Te dane zostały użyte do weryfikacji parametru Pf, określanego jako częstotliwość rozerwania filmu. Parametr ten został użyty w modelu symulacyjnym, który określał wysokość piany w naczyniu. Otrzymane wartości parametru Pf na podstawie modelu, zostały eksperymentalnie zweryfikowane.

18

Wpływ obecności drugiego mieszadła na efekty dyspergowania gazu w cieczy

Kamieński J., Niżnik J.

Inżynieria i Aparatura Chemiczna

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2002

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Nr 4

64-65

PL

Mierzono lokalne wartości średnicy Sautera pęcherzy gazowych rozpraszanych w cieczy przez dwa mieszadła turbinowe tarczowe. Rozpatrzono jej rozkłady wzdłuż promienia aparatu, na różnych jego wysokościach. Analizowano jak obecność drugiego mieszadła, jego położenie i wymiary wpływają na wartości tej średnicy.

EN

The local values of Sauter diameter of bubbles produced during the gas-liquid mixing in a vessel with two Rushton turbines were measured. The distribution of this diameter along the vessel radius as well as at different height was examined. It was analysed how the existence of the second impeller, its location and dimension influence the local values of the diameter.

19

Koalescencja i redyspersja pęcherzy w kolumnie barbotażowej

Pohorecki R., Bielski P., Moniuk W., Zdrójkowski A.

Inżynieria Chemiczna i Procesowa

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2001

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T. 22, z. 3D

1157--1162

PL

W celu określenia wpływu własności fizykochemicznych cieczy na wielkość pęcherzy w procesie barbotażu wykonano pomiary średnicy pęcherzy gazu w laboratoryjnej kolumnie barbotażowej dla siedmiu cieczy organicznych w temperaturze pokojowej i pod ciśnieniem atmosferycznym. Pomiary prowadzono w obszarze przepływu homogenicznego. Wyniki pomiarów porównano z danymi wynikającymi z modelu matematycznego procesów koalescencji i redyspersji pęcherzy.

EN

In order to establish the influence of liquid properties on bubble diameter measurements of bubble diameter were carried out in a laboratory column operated at atmospheric pressure and low temperature, with seven organic liquids. In all experiments free bubbling regime was maintained. The experimentally determined bubble diameters were subsequently compared with the model calculation based on coalescence and break-up processes.