Bubble Stability Research Articles

Influence of surfactant on foam generation and stabilization in cement slurry

Modern civil engineering and industrial buildings use foamed cement because of its low heat conductivity and light weight.Despite their high performance, foamed cement products manufactured solely from cement might be prohibitively expensive for commercial entities. Thus, chemically foaming cement is important. This paper compiles and reviewsthe foamed cement preparation, mostly used physical and chemical foaming processes. Physical foaming creates foamed cement by mixing foam into a slurry. Physical foaming methods are inefficient and energy-intensive. Chemical foaming involves adding a foaming ingredient to cement slurry. Foaming agents like surfactants react to create bubbles that expand the slurry. Surfactants in the liquid solution promote a bubble by spontaneously cicatrizing holes caused by external perturbations. These chemicals stabilize foams and bubbles for minutes to hours. Oil and gas well cementing uses Self-generated nitrogen foam cement (SNFC) with a high-efficiency foam stabilizer. Three surfactants produced cement pastes with and without MWCNT. A viscosity-modifying agent (VMA) in an aqueous cement paste dispersion can change its rheology. Sodium dodecyl sulfate (SDS) and CaCl2 increase nanosilica (NS) fluidity for pumping cement-based grout. FSCGM is used for coal mine infill grouting. Foamed sulfoaluminate cement-based grouting material (FSCGM) makes firefighting CO2 foam. Cement-hollow glass microballoon syntactic foams have greater compressive strength than neat cement at equal densities. Polydentatephosphonate-modified polymers and ester-type polycarboxylate superplasticizers create many cement mortar bubbles (PCE-1). Calcium ions stabilize polymer bubbles. Aqueous epoxy resin is added to cement slurries to reduce plastic viscosity and boost heat conductivity to make high-porosity cement foams (HPCF). Foamed cement bubble stability is highest at particle wetting angle π/2. SDS in silica suspension adjusts this angle. Ti-extraction blast furnace slag (TEBFS) foam with 20–40% sulfoaluminate cement (SAC) makes foamed cement.

Onsite coalescence behavior of whey protein-stabilized bubbles generated at parallel microscale pores: Role of pore geometry and liquid phase properties

In the formulation of (food) foams, an excess of protein is needed to prevent instant coalescence of bubbles from happening at (sub)millisecond time scales. However, protein adsorption and its influences on coalescence stability rarely have been investigated under such conditions of short time scales and high protein concentrations. In the current study, the coalescence stability of whey protein isolate-stabilized bubbles was studied using a microfluidic device, for a wide range of process conditions, including bubble-forming pore geometries and liquid phase properties. The bubble formation time was varied via the applied pressure, and the corresponding extent of bubble coalescence was quantified via the analysis of bubble sizes obtained through high-speed recordings. The experimental results of bubble coalescence as function of bubble formation time, in the presence of various protein concentrations, were also captured in a semi-empirical model. The amount of proteins accumulating at the surface of coalescing bubbles can be derived from a mass balance, with protein adsorption towards the surface of coalescing bubbles assumed to follow a Langmuir isotherm. The model showed a good fit with the experimental results, and we found that as the protein concentration increases from 2.5 to 7.5% wt., in our device the minimum time required to stabilize bubbles decreases from 0.5 to 0.1 ms. From a practical perspective, our microfluidic device can be used as an efficient tool to capture the instant, (sub)milliseconds, behavior of bubble coalescence, providing closer insights for industrial-scale production of (food) foams that also takes place at these time scales.

Ostwald ripening of aqueous microbubble solutions.

Bubble solutions are of growing interest because of their various technological applications in surface cleaning, water treatment, and agriculture. However, their physicochemical properties, such as the stability and interfacial charge of bubbles, are not fully understood yet. In this study, the kinetics of radii in aqueous microbubble solutions are experimentally investigated, and the results are discussed in the context of Ostwald ripening. The obtained distributions of bubble radii scaled by mean radius and total number were found to be time-independent during the observation period. Image analysis of radii kinetics revealed that the average growth and shrinkage speed of each bubble is governed by diffusion-limited Ostwald ripening, and the kinetic coefficient calculated using the available physicochemical constants in the literature quantitatively agrees with the experimental data. Furthermore, the cube of mean radius and mean volume exhibit a linear time evolution in agreement with the Lifshitz-Slezov-Wagner (LSW) theory. The coefficients are slightly larger than those predicted using the LSW theory, which can be qualitatively explained by the effect of finite volume fraction. Finally, the slowdown and pinning of radius in the shrinkage dynamics of small microbubbles are discussed in detail.

Proximity induced moment at Pt/Co interfaces and isolated skyrmion bubble stabilization at zero magnetic field

Magnetic multilayers with heavy metal/ferromagnetic interfaces play an important role in data storage and spintronics due to magnetic phenomena such as perpendicular magnetic anisotropy (PMA) and magnetic skyrmion stabilization. Properties such as saturation magnetization (Ms), PMA, and interfacial Dzyaloshinskii–Moriya interaction (iDMI) can be tuned by stacking engineering to tailor the multilayer magnetic ground state. Here, it is demonstrated that isolated skyrmion bubbles can be stabilized at zero magnetic field in nominally symmetric Pt/Co/Pt multilayers grown by magnetron sputtering. Interface disorder and asymmetry are strongly enhanced as the Co layer is thinned, leading to nonzero iDMI and Pt proximity induced moment (PIM) that affects both the multilayer Ms and PMA. The interplay between PIM and the iDMI is behind the nucleation of skyrmion bubbles, highlighting the importance of controlling the interface phenomena to develop devices for future applications. These results also manifest the importance of considering the PIM to determine the correct magnetic parameters of ultrathin films on the zero-field spin textures stability.

Similar but not equal – A study on the foam stabilisation mechanism of mechanically whipped cream and aerosol whipping cream

Aerosol whipping cream (AWC) enables the quick and easy foaming of cream, but yields foam of a lower stability than mechanically whipped cream (MWC). It was postulated that this is due to the different foaming mechanisms. To verify this, MWC, blank AWC and AWC homogenised with a medium chain saturated monoacylglyceride (me-sMAG-AWC) were foamed and analysed in this study. Foam stabilisation mechanisms were developed by combining results of particle size analysis, foam stability measurements and cryo scanning electron microscopy. For MWC, the known orientated partially coalesced fat globule network was confirmed. A non-orientated beehive structure of partly damaged fat globules was found to stabilise the foam of blank AWC. The stabilisation of the foam of me-sMAG-AWC was caused by a pearl string structure of singular fat globules and by Pickering stabilisation of N2O bubbles by solid fat globules.

Stability of soluble bulk nanobubbles: Many-body dissipative particle dynamics analysis

Bulk nanobubbles (bNBs) have attracted considerable research attention due to their broad application prospects. Numerous experiments have demonstrated the stability of nanobubbles (NBs) in solution, but further investigation is needed to determine their stability mechanism. This paper investigates the properties of bNBs using mesoscopic simulations based on many-body dissipative particle dynamics (MDPD). Based on the standard insoluble bubble model, the soluble bubble model is developed by modifying the attraction amplitude between gas and liquid. This modification determined the range of soluble bubble parameters. The new surface tension calculation model indicates that reducing the surface tension is helpful to the stability of soluble bubbles. In contrast, surface tension changes do not affect the stability of insoluble bubbles. The two bubble models follow the Young-Laplace equation to analyze further the internal density, pressure, gas diffusion, and other characteristics of bNBs. The results show that the gas in bNBs has a high density and pressure. In addition, as the size of the bNBs decreases, the gas density and pressure in the bNBs also increase. In the soluble bubble, the gas density is not uniform, and the gas in the soluble bubble forms a density peak at the gas-liquid interface. The density peak in the bNBs delays the outward diffusion of the gas to maintain its stability. This study aims to provide a method to simulate bNBs, reveal their characteristics, and explore the influence of non-uniform density in bNBs on diffusion.

Evolution of helium bubbles induced by helium irradiation in polycrystalline palladium: An insight into tritium aging

Essential insight into evolution principles of helium (He) bubbles within Palladium (Pd), a prominent hydrogen isotope storage and tritium handling material, is of great importance to understand the service performance of such transition metal in the field of nuclear industry. Particularly, the features of He bubbles and their evolution details have long been attracting broad interests. Herein, He bubbles with different structural features and corresponding distinct evolving processes within polycrystalline Pd were investigated by transmission electron microscopy (TEM), elastic recoil detection (ERD) and thermal desorption spectroscopy (TDS). He bubbles were induced and regulated by irradiation conditions. Comprehensive characterizing results indicate that bubbles with small sizes, spherical shape and uniform distribution, realized by low-fluence irradiation, are inclined to be stable in Pd matrix, while coarsened bubbles with faceted shape and regional distribution in the high-fluence condition are prone to release at relatively low temperatures. Meanwhile the evolving processes of He bubbles including migration, coarsening and releasing within polycrystalline Pd were analyzed. The impact of the structural characteristics such as surfaces or grain boundaries of Pd, acted as “fast path” for bubble diffusion, coarsening and release, was systematically discussed. Moreover, the correlation between tuned irradiation and actual tritium aging was discussed by analyzing He concentrations and bubble sizes in both processes. The study reveals important features of He bubble evolution in Pd, which will provide positive reference for understanding correlative behaviors in other irradiation conditions, especially tritium aging. • He bubbles with different features were obtained by tuning fluence and energy of He + irradiation. • Evolution behaviors of He bubbles including nucleation, migration and coarsening were studied by TEM, ERD and TDS. • The stability of He bubble is closely related to the size that small one inclines to stabilize while large one tends to release. • Trapping and coarsening of He bubbles are promoted in grain boundaries and structural defects. • Different evolution periods of He bubble in this study were analyzed for the purpose to offering an analogous reference for tritium aging.

An optimized recipe for making giant bubbles.

Large bubbles are primarily used in physics laboratories to study 2D turbulence, surface wavers, and fundamental properties of soap systems. Outside of physics, blowing large bubbles is also a part of many performances and shows. Both the scientific and artistic communities usually want to get reasonably stable foam films. The purpose of this article is to propose the main physical ingredients needed for an effective recipe to make stable films and bubbles. We propose controlled experiments to measure both the ease of generating a bubble, and its stability in different stabilizing solutions, which we choose by adding the ingredients contained in a bubble artist's recipe one by one. Our main findings are that (i) the surfactant concentration must not be too high, (ii) the solution must contain long flexible polymer chains to allow for easy bubble generation and (iii) the addition of glycerol provides improved bubble stability by preventing evaporation. Finally, we propose an efficient recipe, which takes into account these considerations.

Mixing carbon nanotubes with asphalt binder through a foaming process toward high-performance warm mix asphalt (WMA)

ABSTRACT This paper investigates mixing carbon nanotubes (CNTs) with asphalt binder through a foaming process to produce high-performance warm mix asphalt (WMA). Two different solvents of ethanol and a water-based surfactant are used to disperse the multi-walled CNTs. Initial morphological assessment of the two CNT solutions showed that a more homogenous dispersion of the CNTs was achieved using the water surfactant solution. The foaming performance, thermal, and rheological properties of the foamed asphalt mixed with different percentages of CNTs are further investigated. The test results showed that a very small amount of CNTs (0.06% ∼ 0.1% in weight of the binder) can effectively enhance the foaming performance for bubble stability without tangibly increasing the rheological properties of the foamed asphalt. The specific heat capacity of the foamed samples was smaller than the neat binder, whereas the glass transition temperature of the foamed samples shifted to a lower temperature as compared to that of the neat binder. The thermal conductivity of the 6% CNTs sample (0.24% wt. in asphalt binder) was improved by two-fold compared with the foamed unmodified asphalt, which indicates the potential of using CNTs in the binder for enhancement of thermal properties in asphalt pavements.

Effect of oily bubbles on the detachment behavior between bubbles and coarse particles

Coarse particle flotation provides significant advantages in terms of reducing grinding costs and improving the throughput of the flotation process. However, the high probability of the detachment of coarse particles during flotation is a significant challenge. In this study, we explored the feasibility of using oily bubbles to reduce the detachment of coarse particles from the bubbles. Specifically, the effect of oily bubbles on the attachment stability of bubble–particle aggregates from the perspective of attachment force was theoretically analyzed and compared to that of air bubbles, and the effect of oily bubbles on the detachment probability of spherical glass beads with different contact angles was investigated experimentally using a home-built experimental system. Both the theoretical and experimental results proved that it is feasible to apply oily bubbles to reduce the detachment probability of coarse particles. However, there are limitations to this method. The influence of oily bubbles on the detachment behavior was mainly governed by changes in the contact angle and interfacial tension, which is not the case with air bubbles. Therefore, the oily bubbles were effective in reducing the detachment probability only for particles in which the influence of the increase in contact angle on the particle detachment exceeded that of the decrease in interfacial tension. The results of this study advance our understanding of the effect of oily bubbles on the detachment behavior of coarse particles, such as in the flotation separation of valuable minerals using oily bubbles.

Bubble behaviors of geldart B particle in a pseudo two-dimensional pressurized fluidized bed

Pressurized fluidized beds have been developed in quite a few industrial applications because of intensified heat and mass transfer and chemical reaction. The bubble behaviors under elevated pressure, strongly influencing the fluidization and reaction conversion of the whole system, are of great research significance. In this work, the bubble behaviors of Geldart B particle in a pseudo two-dimensional (2D) pressurized fluidized bed were experimentally studied based on digital image analysis technique. The effects of pressure and fluidization gas velocity on the general bubble behaviors (i.e., size, shape and spatial distribution) and the dynamic characteristics, such as the time-evolution of voidage distribution and local flow regimes, were comprehensively investigated. Results show that increasing pressure reduces the stability of bubbles and facilitates gas passing through the emulsion phase, resulting in the “smoother” fluidization state with smaller bubbles and declined bubble fraction and standard deviation. The equivalent bubble diameter and bubble aspect ratio increase with the increasing gas velocity while decrease as pressure rises. The elevated pressure reduces bubbles extension in the vertical direction, prohibits the “short pass” of fluidization gas in large oblong bubbles/slugs and benefits the gas–solid interaction. The flow regimes variation with gas velocity is affected by the elevated pressure, and demonstrates different features in different local positions of the bed.

Assessment of bubble activity generated by histotripsy combined with echogenic liposomes

Objective. Histotripsy is a form of focused ultrasound therapy that uses the mechanical activity of bubbles to ablate tissue. While histotripsy alone degrades the cellular content of tissue, recent studies have demonstrated it effectively disrupts the extracellular structure of pathologic conditions such as venous thrombosis when combined with a thrombolytic drug. Rather than relying on standard administration methods, associating thrombolytic drugs with an ultrasound-triggered echogenic liposome vesicle will enable targeted, systemic drug delivery. To date, histotripsy has primarily relied on nano-nuclei inherent to the medium for bubble cloud generation, and microbubbles associated with echogenic liposomes may alter the histotripsy bubble dynamics. The objective of this work was to investigate the interaction of histotripsy pulse with echogenic liposomes. Approach. Bubble clouds were generated using a focused source in an in vitro model of venous flow. Acoustic emissions generated during the insonation were passively acquired to assess the mechanical activity of the bubble cloud. High frame rate, pulse inversion imaging was used to track the change in echogenicity of the liposomes following histotripsy exposure. Main results. For peak negative pressures less than 20 MPa, acoustic emissions indicative of stable and inertial bubble activity were observed. As the peak negative pressure of the histotripsy excitation increased, harmonics of the excitation were observed in OFP t-ELIP solutions and plasma alone. Additional observations with high frame rate imaging indicated a transition of bubble behavior as the pulse pressure transitioned to shock wave formation. Significance. These observations suggest that a complex interaction between histotripsy pulses and echogenic liposomes that may be exploited for combination treatment approaches.

Influence of particle shape on the interaction processes of coal particles and bubbles in saline solution

Understanding the role of coal particle shape in the flotation process is helpful in achieving a clean usage of coal slime flotation. In this investigation, the anthracite coal surface was modified using a chlorinated salt solution containing Na+, Ca2+, or Fe3+. Coal particles with four surface shapes were prepared: angular coal particles (ARPs), prismatic coal particles (PCPs), flat coal particles (FTPs), and spherical coal particles (SLPs). The ARPs were subdivided into five kinds of curvature: 3π/2, 21π/20, 7π/11, π/3, and π/10, and the PCPs were subdivided into five kinds of dihedral angles: 30°, 60°, 90°, 120°, and 150° according to the surface flatness of the ARPs and PCPs. Six ion concentrations, of 0, 5, 10, 20, 40, and 80 mmol/L, were examined. We tested the liquid film drainage time (LDT), maximum repulsive force (MRF), and maximum attractive force (MAF) between these coal particles and bubbles. The results show that at a constant solution concentration for a particular particle shape, the MRFs and LDTs increase in the order of Fe3+<Ca2+<Na+, and the MAFs decrease in the order of Fe3+>Ca2+>Na+. This indicates that Fe3+ enhances the adhesion probability and stability of anthracite particles and bubbles by the greatest extent, followed by Ca2+ and Na+. For a particular shape of coal particles, an increase in the ion concentration reduces the LDT and MRF and increases the MAF. When the curvature of the ARPs is 3π/2 and the dihedral angle of PCPs is 30°, the order of the LDTs of coal particles and bubbles is ARP < PCP < SLP < FTP. With a decrease in the curvature of ARPs and an increase in the dihedral angles of PCPs, their LDTs gradually approaches that of the FTP. The results for MRF and MAF are consistent with the LDT. Therefore, the ARPs with larger curvature and PCPs with smaller dihedral angles easily attach to air bubbles, and the decrease of the curvature and the increase of dihedral angles hindered the detachment. Adhesion and detachment experiments were conducted to confirm these results. The coal particles had a tendency to contact the bubbles with their available tips while sliding on the surfaces of bubbles to induce liquid film rupture. In addition, regardless of the coal particle shape, increasing ion concentration changes the detachment position of coal particles. These findings are consistent with the results of LDT, MRF, and MAF measurements. In this study, the role of coal particle shape in saline solution were systematically investigated, which provides a possible solution for the problems caused by the presence of ions in the flotation process using saline as the water source.

Bubble Evolution under the Action of Polycarboxylate and Air-Entraining Agent and Its Effects on Concrete Properties-A Review.

In order to improve the performance of concrete, it is of great significance to have a better understanding the mechanism and main influencing factors of concrete bubble evolution under the action of polycarboxylate and air-entraining agents. In the present review, with respect to the generation, growth, stability, and rupture of concrete bubbles under the action of polycarboxylate and air-entraining agents, this paper discusses the influence of bubble characteristics on concrete performance and studies bubble regulation by air-entraining agents and polycarboxylate (PCE) superplasticizer. The results show that the acid-to-ether ratio, sulfonic acid group, ester group, and the type of air entraining agent of the polycarboxylate acid structure have a significant impact on the bubbles. The bubble size, specific area, spacing factor, and bubble content have a significant impact on the rheological properties and related mechanical properties of fresh concrete and also affect the appearance quality of concrete. The problems with the experimental methods and theoretical models of concrete bubble research were analyzed, and future research ideas were put forward.

Study on directional enhancement effect of underwater explosion for cylindrical explosive with large length-to-diameter ratio and structural response of nearby water-back plate

In order to study the directional enhancement effect of underwater explosion for cylindrical explosive with large length-to-diameter ratio, based on the experiment and ALE method, the influences of length-to-diameter ratio on the shock wave and bubble load as well as the structural response of nearby water-back copper plate are analysed. Meanwhile, the influence of the explosive weight on the directional enhancement effect is considered. Some instructive conclusions can be drawn. i) As the length-to-diameter ratio increases, the propagation velocity increases in the radial direction and decreases in the axial direction, and the high-pressure area gradually concentrates in the radial direction. ii) In the range of 1:1–8.2:1, increasing the length-to-diameter ratio enhances the shock wave and bubble load in the top direction and facilitates the formation of a stable bubble jet in this direction. iii) Increasing the length-to-diameter ratio enhances the damage effect of combined load in the top and bottom directions. When the length-to-diameter ratio increases from 1:1 to 8.2:1, the maximum plastic deformation of the water-back copper plate is increased by 26.2%. iv) The directional enhancement effect will be more obviously if the maximum bubble radius is larger than the distance between the structure and the explosive.

Shape deformations and instabilities of single bubble rising in liquid metals

In this study, a computational fluid dynamics simulation was used to study single bubble flow in liquid metal. Until now, bubble trajectory and shape [Mougin, G. and Magnaudet, J., “Path instability of a rising bubble,” Phys. Rev. Lett. 88, 014502 (2002)] stability problems in liquid metal have only been insufficiently analyzed in the literature. Because of the difficulty of such an experimental validation, no universal correlations on terminal velocity, shape aspect ratio, and drag force coefficient have been produced to date. The existing bubble shape parameter and terminal velocity correlations with dimensionless numbers are still debatable, mostly because experimental validation is very challenging. The objective of this study was to develop new correlations between bubble stability and bubble deformation in liquid metals. An in-house code, PSI-BOIL, has been used for the simulations. A single bubble rising in a quiescent liquid has been simulated for three different sets of materials (nitrogen+mercury, argon+GaInSn, and argon+steel). The obtained results suggest that shape instability phenomena take place in the bubble dynamics in liquid metals for Eötvös numbers &amp;gt;1.7. Small bubbles (Eo &amp;lt; 1.7) maintain a stable ellipsoidal shape, while the shape and velocity of larger bubbles (Eo &amp;gt; 1.7) tend to oscillate with bubbles rising via non-rectilinear trajectories. The inviscid approximation works well for bubbles in liquid metals. It has been confirmed that the dynamics and the shape of small bubbles (Eo &amp;lt; 1.7) in liquid metals are only controlled by the Weber number.

Air-in-liquid compound drop impact onto a pool

We investigate numerically the dynamics of a drop containing a bubble impacting onto a pool of the same liquid. We show that the bubble can be engulfed into the pool after impact only for a limited range of impact velocities and bubble sizes. Below a critical Weber number, the compound drop bounces from the surface. By contrast, above a second threshold in Weber number, the bubble bursts during impact. Depending on the bubble size, we identify two different mechanisms responsible for this higher impact velocity threshold, with central bursting at lower bubble sizes, or dimple bursting at larger bubble sizes. We then characterize and model the dynamics of the cavity, to finally provide an overview of the mechanisms affecting the bubble stability in the liquid.

Ultralight, super thermal insulation, and fire-resistant cellular cement fabricated with Janus nanoparticle stabilized ultra-stable aqueous foam

Bubble-templated advanced cellular materials with ultralight and superior thermal insulation properties have shown great potential in energy-saving related applications. However, insufficient bubble stability severely limits the generation of such highly porous structures. Herein, we present an efficient method to produce ultra-stable aqueous foams by combing the amphiphilic Janus nanoparticle (Janus-SiO2) with the surface-active polymer (hydroxypropyl methylcellulose). The life of aqueous foams is dramatically increased from 4 h to over 5 days with 5 wt% Janus-SiO2 concentration. The dense adsorbed layer formed by the efficient adsorption of Janus-SiO2 on the bubble film is the main factor for the outstanding foam stability. Owing to the greatly enhanced foam stability, we successfully produce ultralight cellular cement with hierarchical cellular structures and a density as low as 80 kg/m3. The ultralight cellular cement exhibits superior mechanical strength, robust fire resistance and excellent thermal insulation with a thermal conductivity as low as 0.038 W·m−1·K−1. This work provides a practical approach for fabricating various advanced porous materials that employ bubbles as templates.

Microfluidics investigation of the effect of bulk nanobubbles on surfactant-stabilised foams

In aqueous foams, the bubble size usually spans from tens of microns to centimetres. However, it is possible to create much smaller and stable bubbles in solutions: nanobubbles have diameters well below a micron. Many issues are still pending on nanobubbles, especially regarding their stability. Here, we address if and how the addition of nanobubbles may change the interfacial and foaming properties of surfactant solutions. Using a first microfluidic device, nanobubbles are formed within the aqueous surfactant solutions (SDS and Triton X-100 at different concentrations). A second microfluidic device then generates foams from these solutions. Additionally, we report systematic results on the interfacial and bulk properties of such solutions. Finally, we show that nanobubbles have some effects on almost all the measured quantities; however, the most striking one is enhancing the foaming of the solutions with an initial poor foamability. These measurements provide us with a comprehensive set of new results allowing us to draw a first multi-scale picture of how far nanobubbles could potentially act as foam boosters and stabilizers or be implemented in colloidal formulations. Yet, more investigations are required to unravel the mechanisms leading to our results.

Effect of oil-based emulsion on air bubbles in the spray sheet produced through the air-induction nozzle.

The air-induction spray featured by air bubbles involved in the spray sheet has attracted great attention in applications of agricultural spray due to its advantages of alleviating spray drift and promoting deposition. The objective of the presented study is to deepen the understanding of the mechanism of the air-induction spray through elucidating the effect of sprayed liquid on characteristics of air bubbles in the spray sheet. The air bubbles with relatively large sizes are stable for a long time span. As velocity of the water spray increases from 6.85 m s-1 to 17.87 m s-1 , average size of the air bubbles decreases from 383.21 μm to 236.47 μm. With the introduction of organosilicone surfactant, the surface tension of the sprayed liquid decreases from 67.38 mN m-1 to 31.32mN m-1 ; accordingly, average size of the bubbles decreases from 383.21 μm to 160.9μm. Compared to aqueous solutions spray, the oil-based emulsion spray is responsible for relatively small average size of air bubbles as the surface tension and spray velocity are respectively similar. Low drainage rate of the bubble lamella contributes to high stability of large air bubbles. The decrease of the average size of air bubbles is responsible for small volumetric median diameter of oil-based emulsion spray compared with water spray. Besides the increase of the spray velocity and the decrease of the surface tension, the Marangoni effect caused by dynamics of oil droplets at air-liquid interface also contributes to the decrease of average size of air bubbles. © 2022 Society of Chemical Industry.