Droplet Diameter Research Articles

Accurate predictions of mist assisted film cooling characteristics and effectiveness on a flat plate with double-row holes

Improving the multi-row film cooling effectiveness of turbine vanes and blades is becoming increasingly important, and the configuration design of the multi-row holes is becoming increasingly complex. This paper presents a simulation study of the air/mist film cooling characteristics on double-row-hole flat plates and makes predictions about spanwise-averaged cooling effectiveness using a modified Sellers superposition method. The effects of blowing ratio, row spacing, row arrangement, droplet diameter, and mist mass ratio on film cooling are systematically investigated. It is found that the injected mist improves the film cooling effectiveness under all operating conditions for the coolant air. The air/mist cooling is particularly effective at a blowing ratio of 1.25 or a row spacing of 5D with the staggered two-row holes. The improvement in cooling effectiveness increases with increasing mass ratio or decreasing droplet diameter of the mist. Furthermore, the spanwise-averaged cooling effectiveness can be accurately predicted by modifying the classical Sellers superposition model. This study lays the foundation for accurately predicting the distribution of air/mist film cooling effectiveness of turbine vanes and blades, and helps to promote the development of practical air/mist film cooling technology.

Physicochemical Stability of Hospital Parenteral Nutrition Solutions: Effect of Changes in Composition and Storage Protocol.

(1) Background: Parenteral nutrition (PN) is a technique used for the administration of nutrients to patients for whom traditional routes cannot be used. It is performed using solutions with extremely complex compositions, which can give rise to a large number of interactions. These interactions can impact their stability and put the patient's life at risk. The aim of this study is to determine how changes in composition and storage protocol affect the stability of NP solutions. (2) Methods: Twenty-three samples were prepared according to routine clinical practice, with modifications to the concentration of some components. The samples were stored at room temperature (RT) and refrigerated (4 °C). Measurements of the droplet diameter, pH, density and viscosity were performed for both storage protocols on days 1, 3, 10 and 14. (3) Results: The samples with the lowest concentration of lipids (PN13-17) and proteins (PN18-22) showed a larger droplet diameter than the rest of the samples throughout the experiments. The USP limits were exceeded for some of the measurements of these sample groups. The pH density and viscosity remained relatively constant under the conditions studied. (4) Conclusions: The PN samples were considered stable and safe for administration under real-world conditions, but the samples with the lowest concentrations of lipids and proteins showed a tendency towards emulsion instability.

CFD-PBM coupled modeling of the liquid-liquid dispersion characteristics and structure optimization for Kenics static mixer

Kenics static mixers (KSM) are extensively used in industrial mixing–reaction processes by virtue of high mixing efficiency, low power homogenization and easy continuous production. Resolving liquid droplet size and its distribution and thus revealing the dispersion characteristics are of great significance for structural optimization and process intensification in the KSM. In this work, a computational fluid dynamics–population balance model (CFD–PBM) coupled method is employed to systematically investigate the effects of operating conditions and structural parameters of KSM on droplet size and its distribution, to further reveal the liquid–liquid dispersion characteristics. Results indicate that higher Reynolds numbers or higher dispersed phase volume fractions increase energy dissipation, reducing Sauter mean diameter (SMD) of dispersed phase droplets and with a shift in droplet size distribution (DSD) towards smaller size. Smaller aspect ratios, greater blade twist and assembly angles amplify shear rate, leading to smaller droplet size and a narrower DSD in the smaller range. The degree of impact exerted by the aspect ratio is notably greater. Notably, mixing elements with different spin enhance shear and stretching efficiency. Compared to the same spin, SMD becomes 3.7–5.8 times smaller in the smaller size range with a significantly narrower distribution. Taking into account the pressure drop and efficiency in a comprehensive manner, optimized structural parameters for the mixing element encompass an aspect ratio of 1–1.5, a blade twist angle of 180°, an assembly angle of 90°, and interlaced assembly of adjacent elements with different spin. This work provides vital theoretical underpinning and future reference for enhancing KSM performance.

Performance and mechanism of atomizing dust removal from APG12/Active Water: Experimental and molecular simulation study

Coal mining processes produce large amounts of dust particles that seriously pollute the environment and threaten health. Spraying technology is a primary technique for dust removal. To date, experimental methods are mainly applied to study the atomization and dust removal properties of water droplets, but the intermolecular mechanism involved is unclear. First, a test platform was assembled to evaluate the atomization and dust removal performance of APG12/active water. Then, APG12 droplet and APG12 droplet/anthracite molecular models were constructed, and the underlying mechanism was elucidated through molecular simulation. The experimental results showed that the droplet diameter of the APG12/active water spray decreased by 14.15%, and the dust removal efficiencies of total dust and respirable dust increased by 39.55% and 61.51%, respectively. The simulation results indicated that APG12 molecules and H2O molecules exhibited attractive interactions. This interaction weakened the electrostatic attraction between the H2O molecules in the APG12/active water droplets. Moreover, the interaction enhanced the repulsive van der Waals interactions, reduced the number of hydrogen bonds, and increased the diffusion coefficient of H2O molecules. As a result, the droplets were relatively easy to break. In addition, APG12 molecules covered the surfaces of anthracite molecules, thus increasing the surface oxygen content and the electrostatic attraction, van der Waals forces and hydrogen bonding between H2O and coal molecules. This enhancement, in turn, improved the wettability of coal dust. Herein, the molecular mechanism of dust removal from APG12/active water was analysed, providing guidance for the development of new dust suppressants.

Effect of Entrainment on the Liquid Film Behavior in Pipe Elbows

Multiphase flow entrainment in natural gas engineering significantly influences the safety and efficiency of oil companies since it affects both the flow and the heat transfer process, but its mechanisms are not fully understood. Additionally, current computational fluid dynamics (CFD) methodologies seldom consider entrainment behavioral changes in pipe elbows. In this article, a verified CFD method is used to study the entrainment behavior, mechanism, and changes in an elbow. The results show that droplet diameter in a developed annular flow follows a negative skewness distribution; as the radial distance (from the wall) increases, the fluctuation in the droplets becomes stronger, and the velocity difference between the gas and the droplets increases linearly. Turbulence bursts and vortices sucking near the wall jointly contribute to droplet entrainment. As the annular flow enters the elbow, the secondary flow promotes the film expansion to the upper and lower parts of the pipe. Droplets re-occur near the elbow exit intrados, and their size is much smaller than those in the upstream pipe. Vortices sucking under low gas velocity play an important role in this process. These findings provide guidelines for safety and flow assurance issues in natural gas production and transportation and bridge the gap between multiphase flow theory and natural gas engineering.

Development of plant-based whole egg analogs using emulsion technology

RuBisCO is a plant protein that can be derived from abundant and sustainable natural resources (such as duckweed), which can be used as both an emulsifying and gelling agent. Consequently, it has the potential to formulate emulsion gels that can be used for the development of plant-based replacements of whole eggs. In this study, we investigated the ability of RuBisCO-based emulsion gels to mimic the desirable properties of whole eggs. The emulsion gels contained 12.5 wt% RuBisCO and 10 wt% corn oil to mimic the macronutrient composition of real whole eggs. Initially, an oil-in-water emulsion was formed, which was then heated to convert it into an emulsion gel. The impact of oil droplet diameter (∼15, 1, and 0.2 μm) on the physicochemical properties of the emulsion gels was investigated. The lightness and hardness of the emulsion gels increased as the droplet size decreased, which meant that their appearance and texture could be modified by controlling droplet size. Different concentrations of curcumin (3, 6, and 9 mg/g oil) were incorporated into the emulsions using a pH-driven approach. The curcumin was used as a natural dual functional ingredient (colorant and nutraceutical). The yellow-orange color of curcumin allowed us to match the appearance of raw and cooked whole eggs. This study shows that whole egg analogs can be formulated using plant-based emulsion gels containing natural pigments.

A simplified drop breakage model for emulsion-producing fluidic devices: Application to fluidic oscillator, helical coil and vortex-based cavitation device

Droplet size distribution (DSD) is one of the key quality attributes of liquid–liquid emulsions. Various fluidic devices are used to generate emulsions. Most of the currently available models for estimating DSD are complicated to implement and computationally expensive. In this work, we have developed a simplified drop breakage model that is easy to implement and computationally inexpensive. This model approximates DSDs in three droplet populations, each characterised by a mean diameter. The developed drop breakage model was applied to simulate Sauter mean diameters of oil-in-water emulsions generated using three fluidic devices covering a broad range of shear rates and droplet sizes namely: vortex-based cavitation device (VD), helical coil (HC), and fluidic oscillator (FO). The variation of DSD with the number of passes (np) through the emulsion-producing fluidic devices was measured experimentally. The Sauter mean diameter (d32) and number of droplets (n) in each population were estimated from the measured DSD data. The procedure to estimate model parameters is presented. The simplified breakage model presented here was able to simulate the influence of the number of passes and operating conditions on Sauter mean diameter as well as breakage efficiency. VD was found to exhibit the highest drop breakage efficiency. FO was found to be a preferred choice for low (< 20 J/kg) energy consumption, HC for the middle range (20 – 100 J/kg) and VD for the higher (> 100 J/kg) range of energy consumption. The developed approach and model provide a simplified way of simulating the Sauter mean diameters of emulsions for a variety of emulsion-generating devices.

Study on trapping behaviour of SiO2-containing droplets on the solid surface

The dynamic behaviour of droplets impacting solid surfaces exists in nature, production, and life. In this paper, for the first time, the molecular dynamics method is used to simulate capturing the behaviour of nanodroplets containing SiO2 on solid surfaces. The dynamic behaviour of nanodroplets impacting solid surfaces is analysed when the initial falling velocity v0 of the droplet is 0.3–1.5 nm·ps−1 and for different particle size ds, mass fraction φs of SiO2, and solid surfaces with various wettability. The contact angles of droplets containing SiO2 nanoparticles on the solid surface were measured, and the simulated values closely matched experimental results. The results show that the droplets on the smooth solid surface are completely captured after impact when v0 = 0.3–1.1 nm·ps−1. When v0 = 1.2–1.5 nm·ps−1, the droplet is fragmented, and the fragmentation ratio ns increases with the mass fraction φs. The droplet fragments when v0 = 1.4–1.5 nm·ps−1 on the rough solid surface when the ratio of the side length of the square column to the droplet diameter is 0.07, while the pure water droplet directly bounces and does not fragment. There is a linear relationship between the minimum height of the centre of mass and the mass fraction in the process of droplet impact. The maximum droplet’s spreading factor value in the spreading stage βmax increases with mass fraction φs and v0. When the spreading factor of droplets increases to βc ≈ 3.02, the droplet fragments. The droplet spreading presents the Wenzel state on the rough solid surface. Moreover, the pinning effect affects the droplet falling into the square column gap surface, hindering droplet spreading. Therefore, the rough surface has better catching ability for the droplet than the smooth surface, while the speed range that can be caught is larger. These results provide a theoretical basis for related engineering applications.

Performance Characterisation of the Airvo2TM Nebuliser Adapter in Combination with the Aerogen SoloTM Vibrating Mesh Nebuliser for in Line Aerosol Therapy during High Flow Nasal Oxygen Therapy.

High flow oxygen (HFO) therapy is a well-established treatment in respiratory disease. Concurrent aerosol delivery can greatly expediate their recovery. The aim of this work was to complete a comprehensive characterisation of one such HFO therapy system, the Airvo2TM, used in combination with the Aerogen SoloTM vibrating mesh nebuliser. Representative adult, infant, and paediatric head models were connected to a breathing simulator via a collection filter placed at the level of the trachea. A tracheostomy interface and nasal cannulas were used to deliver the aerosol. Cannula size and gas flow rate were varied across the full operating range recommended by the manufacturer. The tracheal and emitted doses were quantified via UV-spectrophotometry. The aerosol droplet diameter at the exit of the nares and tracheal interface was measured via cascade impaction. High gas flow rates resulted in low emitted and tracheal doses (%). Nasal cannula size had no significant effect on the tracheal dose (%) available in infant and paediatric models. Higher gas flow rates resulted in smaller aerosol droplets at the exit of the nares and tracheostomy interface. Gas flow rate was found to be the primary parameter affecting aerosol delivery. Thus, gas flow rates should be kept low and where possible, delivered using larger nasal cannulas to maximise aerosol delivery.

Design and performance analysis of a piezoelectric jetting dispensing valve

In order to meet the requirements of high frequency, high precision, and micro-scale dispensing in the field of microelectronics packaging, a piezoelectric jetting dispensing valve based on two-stage displacement amplifying mechanism was proposed. First, the overall structure and working principle of the proposed piezoelectric jetting valve were described. The displacement amplifying mechanism was designed, and the mathematical relationship between the output displacement and the structural parameters was established. In addition, the performance and the structural size of the displacement amplifying mechanism were analyzed and optimized by using the finite element analysis software. The influences of driving pressure, glue viscosity, needle displacement, and other parameters on droplet diameter and jetting velocity in the process of dispensing were simulated and analyzed. In order to obtain the optimal nozzle structure, the changing curves of glue flowing velocity with different nozzle seal forms, nozzle cone angles, and outlet inner diameters were compared and analyzed. Finally, the prototype of the piezoelectric jetting dispensing valve was machined, and experimental study was performed. The influence laws of driving pressure, glue viscosity, driving voltage, and other parameters on the diameter of droplet were explored. The performance of the prototype was evaluated from three aspects of dispensing frequency, consistency, and minimum dispensing droplet diameter. Results show that the highest dispensing frequency is 230 Hz, the deviation of dispensing consistency is ±8.77%, and the minimum dispensing droplet diameter is 0.54 mm. The experimental results verify the high frequency, consistency, and micro-scale dispensing performance of the piezoelectric jetting dispensing valve based on the displacement amplifying mechanism, which provides a reference for the research of piezoelectric high-frequency jetting dispensing.

Characterization of nasal spray aerosol fields using the extended interferometric particle imaging technique

Nasal-drug-delivery is an effective way to improve therapeutic effect. Droplet diameter and its distribution directly impact the deposition position and bioavailability of the drug in nasal passage. In this paper, the spatial distribution of the droplet size, location and refractive index of spray are explored with extended interferometric particle imaging technique. A generalized expression of the spatial spacing of interference fringes is derived theoretically. The fringe spacing for two counter-propagating beams is the same as that for a single beam along one of the two-beam directions at the sideward scattering region, which is verified by simulation and experiment. The polystyrene microsphere and the nasal spray of physiological saline and oxytocin are tested experimentally. The relative error of microsphere size is less than 0.3 %, the refractive index accuracy of spray can reach 10−4. The method presented herein is promising for many relevant applications, such as fuel spray and nasal spray.

Droplet deposition behavior on the surface of wheat leaves with wind-induced vibration

Droplet impingement on leaf surfaces is a common phenomenon in the spray application process. Most impingements have focused on droplet deposition behavior on stationary leaf surfaces. However, airflow movement and auxiliary airflow during the spray application process create disturbances and generate vibrations on the leaves, which would inevitably affect the deposition conditions of droplets on leaf surfaces. A three-dimensional “droplet-leaf vibration” Computational fluid dynamics (CFD) simulation model is constructed in this paper, and model validation and simulation tests are performed to investigate the effects of leaf vibration on droplet deposition. Experimental results reveal that when the droplet velocity is 1 m/s, with a 60° inclination angle and a vibrational angular velocity of 9 rad/s, the spreading area factor of a 200-μm droplet has the greatest increase up to a value of 1.34, and vibrational effects on the deposition behavior of the three droplet diameters demonstrate a consistent trend.Compared to stationary leaves, vibrating wheat leaves can alter the impingement behavior of droplets close to critical conditions, and vibration can also increase the sliding range for droplets. Vibration in wheat leaves can promote droplet spreading and deposition and increase the spreading area of droplets on the leaf surface. The effects of vibration on large-diameter droplets are more significant compared to small-diameter droplets, where droplet spreading and movement can be effectively enhanced. This paper shall provide a three-dimensional “droplet-leaf vibration” CFD simulation method, providing novel research ideas for the study of droplet deposition behavior on vibrating leaves.

Extremely large water droplet impact onto a deep liquid pool.

Most studies of droplet impact on liquid pools focus on droplet diameters up to the capillary length (0.27cm). We break from convention and study extremely large water droplets (1 to 6cm diameter) falling into a pool of water. We demonstrate that the depth and width of the cavity formed by large droplet impact is greatly influenced by the deformed shape of the droplet at impact (i.e., prolate, spherical, and oblate), and larger droplets amplify this behavior by flattening before impact. In particular, the maximum cavity depth is a function of the Froude number and axis ratio of the droplet just before impact. Further, the cavity depth is more dependent on the droplet height than width, and the maximum cavity diameter is independent of the droplet height. In general, we observe that more oblate droplets result in decreasing cavity depths for a fixed liquid volume. This is because an increase in horizontal droplet diameter results in a reduced impact energy flux and therefore reduced cavity depth.

Model-based investigation of a novel decontamination technology: Ultrasound assisted aerosolized hydrogen peroxide

This work investigates the feasibility of a novel decontamination technology that employs ultrasonic acoustic streaming to improve aerosol distribution inside isolator chambers. For this purpose, a numerical model consisting of three simulations (i) acoustic pressure, (ii) fluid flow, and (iii) particle tracing, is developed. Acoustic air streaming is examined for ultrasound source pressure levels between 131 and 136 dB. Maximum streaming velocity reached values of the order 10−3 and 10−2m/s which agrees with previous experimental and numerical investigations. The effect of air velocity field on the deposition of the decontamination agent on the isolator floor was assessed for aerosol with droplet diameter between 10 and 20μm. The results show that a more homogeneous distribution of deposited droplets is obtained with configurations that have sound sources placed at a distance from each other. Designs with a homogeneous aerosol deposition are expected to have a better decontamination outcome.

LES of autoignition process in a turbulent droplet-laden mixing layer – impact of an evaporation model and discretisation method

This paper focuses on the numerical modelling of the autoignition process in an ethanol-air mixture within a turbulent droplet-laden temporally evolving mixing layer, utilising the Large Eddy Simulation (LES) method. We compare results obtained by implementing two notably distinct discretisation methods (second-order Total Variation Diminishing – TVD, and fifth-order Weighted Essentially Non-Oscillatory – WENO) in the species and energy transport equations. Additionally, we examine three widely recognised evaporation models (the ‘ D 2 ’ model, the Abramzon–Sirignano model, and a non-equilibrium model based on the Langmuir-Knudsen law). For modelling the combustion process, we employ the Eulerian Stochastic Field method and a laminar chemistry model. The simulations encompass two droplet diameter distributions, one with low and the other with significant diameter non-uniformity. Furthermore, nine distinct initial conditions are considered. Our findings indicate that adjusting the discretisation scheme or the evaporation model can yield simulation outcomes differing to a substantial degree, similar to the impact of modifying the actual properties of the spray droplets or their initial distribution. This is particularly pronounced in the case of sprays featuring a narrowed droplet diameter distribution. We found that the Abramzon–Sirignano model results in the most rapid autoignition. The TVD scheme contributes to a more even spatial distribution of the evaporated fuel, consequently facilitating quicker evaporation and faster autoignition. Using the WENO scheme generates higher fuel vapor gradients near the droplets, leading to less intense evaporation and slower fuel transport in space.

Effect of ultrasonic power on delivery of quercetin in emulsions stabilized using octenyl succinic anhydride (OSA) modified broken japonica rice starch

In this study, emulsions stabilized by octenyl succinic anhydride-modified broken japonica rice starch (OSA-BJRS) were prepared at different ultrasonic power intensities for the delivery, controlled release, and improved bioavailability of quercetin. The OSA-BJRS emulsions ultrasonicated at 400 W exhibited the highest encapsulation efficiency (89.37 %) and loading efficiency (58.34 %) of quercetin, the smallest volume-average droplet diameter (0.51 μm) and polydispersity index (0.19), the highest absolute value of the ζ-potential (26.73 mV), and the highest apparent viscosity and viscoelasticity. The oxidation stability, storage stability, thermal stability, and salt ion stability of the emulsions were also notably improved by the ultrasonication treatment. In addition, the results of the simulated in vitro digestion demonstrated that the ultrasonicated OSA-BJRS emulsions had an enhanced quercetin delivery performance and could stably transport quercetin to the small intestine for digestion. The OSA-BJRS emulsion ultrasonicated at 400 W exhibited the highest cumulative release rate (95.91 %) and the highest bioavailability (30.48 %) of quercetin. This suggests that OSA-BJRS emulsions prepared by ultrasonication can be considered effective delivery systems for hydrophobic functional components.

Experimental Study of the Effect of the Initial Droplet Diameter on the Evaporation Characteristics of Unsymmetrical Dimethylhydrazine Droplets in a Subcritical Environment

The evaporation characteristics of unsymmetrical dimethylhydrazine droplets with different initial diameters in a subcritical environment were experimentally investigated with the temperature–pressure separation technique. The evaporation processes of unsymmetrical dimethylhydrazine droplets with different initial diameters in this environment have the same general pattern. All the studied droplets exhibit a short transient heating phase and a steady-state evaporation phase obeying d2. Notably, the expansion of the transient heating phase gradually increases with increasing ambient pressure. The change in diameter squared ∆d2max increases from 1.03% at 1 MPa to 12.48% at 5 MPa. Under subcritical conditions, the evaporation rate decreases linearly with decreasing droplet diameter, and the droplet evaporation lifetime increases linearly. Changes in the initial droplet diameter may still have a large effect on droplets smaller than those studied here. When the ambient pressure is not greater than 3 MPa, the change in the steady-state evaporation time for both medium- and large-diameter droplets accounts for more than 70% of the variation in the droplet evaporation lifetime. As the ambient pressure increases to 4 MPa and 5 MPa, the percentage of the change in the transient heating time contributing to the variation in the droplet evaporation lifetime gradually increases to more than 45%.

Variation of glyphosate spray volume in the drying of ground cover plants with an unmanned aerial vehicle

The presence of straw on the soil is crucial for enhancing its physical, chemical, and biological conditions in no-tillage cropping systems, while contributing to weed control. This study aimed to determine the optimal spray volume for desiccating ground cover plants using glyphosate applied by an unmanned aerial vehicle (UAV). Treatments included an untreated control and glyphosate spraying at 5, 10, 15, 20, and 25 L ha−1 spray solution. The study was conducted in three fields in the State of Paraná, Brazil. Spraying variables were assessed using water-sensitive paper and the e-Sprinkle software, and included, covered area (%), recovered spray volume (L ha−1), droplet impact density, coefficient of variation for droplet diameter (CV%), and relative amplitude (SPAN). Herbicidal efficacy and dry biomass of cover plants were also evaluated. Increasing spray volume improved covered area, recovered volume, droplet impact density, and droplet diameter-spectrum variation but had no effect on droplet spectrum homogeneity, control of black oat (Avena strigosa), turnip (Raphanus sativus), or buckwheat (Fagopyrum esculentum). Spray volumes ranging from 5.0 to 25 L ha−1, applied with a UAV, provided satisfactory desiccation percentages of ground cover plants irrespective of species or location. Thus, for desiccating ground cover plants with glyphosate applied by UAV, a volume as low as 5.0 L ha−1 is effective.

Integration of wide-field imaging system with droplet microfluidics for monitoring living bacteria

Droplet microfluidics has been widely used to analyze chemicals and biological reactions at the single-molecule level. Microscopic systems are commonly used for imaging and analyzing droplets using high-magnification objective lenses. However, these systems are expensive, complex, and large, limiting the high-throughput characterization of droplets in reactions targeting disease-related biomarkers, including nucleic acids, proteins, and pathogens. Another concern is the time gap between droplet analysis within a microfluidic channel and imaging chamber, which can cause discrepancies in reaction time between droplets. To address this issue, we introduce the droplet analysis system for vast imaging and statistical tool (DropVIST)—a wide-field imaging system integrated with droplet microfluidics for rapid and accurate droplet analysis. DropVIST can detect eight differently colored droplets simultaneously using a wide-field imaging system and dFinder software, which can quantify the reacted droplets. The smallest droplet diameter for detection was 30 μm, and the maximum detection area was 201.84 cm2, suggesting that the system can theoretically analyze 3103,377 droplets in real-time. We validated the monitoring performance of DropVIST using clinical isolates of five types of living pathogenic bacteria and compared this with conventional approaches, including the microbroth dilution method and colony-forming unit assay. This platform provides a rapid, simple, and accurate tool for monitoring living bacteria at the single-cell level.

Bubble dynamics and atomization of acoustically levitated diesel and biodiesel droplets using femtosecond laser pulses

This study focuses on the bubble dynamics and associated breakup of individual droplets of diesel and biodiesel under the influence of femtosecond laser pulses. The bubble dynamics were examined by suspending the droplets in the air through an acoustically levitated setup. The laser pulse energies ranged from 25 to 1050 µJ, and droplet diameters varied between 0.25 and 1.5 mm. High-speed shadowgraphy was employed to examine the influence of femtosecond laser intensity and multiple laser pulses on various spatial–temporal parameters. Four distinct sequences of regimes have been identified, depending on early and late times: bubble creation by individual laser pulses, coalescence, bubble rupture and expansion, and droplet fragmentation. At all laser intensities, early-time dynamics showed only bubble generation, while specifically at higher intensities, late-time dynamics revealed droplet breaking. The droplet breakup is further categorized into three mechanisms: steady sheet collapse, unstable sheet breakup, and catastrophic breakup, all following a well-known ligament and secondary breakup process. The study reveals that laser pulses with high repetition rates and moderate laser energy were the optimal choice for precise bubble control and cutting.