Jiajun Cui¹, Fabian Reuter², Zhigang Zuo^1,*, Shuhong Liu^1,*, Claus-Dieter Ohl^2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.4, pp. 1-1, 2024, DOI:10.32604/icces.2024.012155

Abstract When cavitation bubbles collapse near a boundary, they can cause severe cavitation erosion to the boundary, which is a dangerous threat to the rapidly rotating turbines. Prior research has established that for single bubbles a possible mechanism is energy focusing of shockwaves during the non-spherical collapse of cavitation bubbles [1]. This however needs a particularly symmetric environment. A possible approach to reduce the shockwave focusing and thus the erosion would be through suitable modification of the boundary. In a first approach to modify this phenomenon, we introduce the symmetry breaking structure on the boundary in the shape of a slender bar to explore the effect More >

Jie Wang^1,*, Jingyu Gu¹, Shuai Li¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.012184

Abstract The interaction between the particle and the bubble under the ultrasonic wave excitation plays a pivotal role in various applications such as targeted therapy, ultrasonic cleaning, ultrasonography, and microbubble motors. When the particle is in close proximity or even attached to the bubble, a strong fluid-structure interaction occurs, significantly influencing the particle propulsion. The attachment of the bubble to the particle results in distinct bubble pulsation patterns and particle acceleration mechanisms from the non-contact state. Thus, we propose a fluid-structure interaction model based on the boundary integral method (BIM) to comprehensively consider the distance between More >

Wentao Wu¹, Qingyun Zeng^1,2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.2, pp. 1-2, 2024, DOI:10.32604/icces.2024.012089

Abstract The collapses of bubbles near rigid walls are seen widely in engineering and medical applications, examples are surface cleaning, sonoporation, under water explosion, and cavitation erosions, to name a few. Recent experimental studies demonstrated that only bubbles with extremely small stand-off distance γ (γ = d/Rmax, γ is stand-off distance, d is the initial distance of the bubble center to the boundary, and Rmax is the maximum radius the bubble would attain) generate severe erosions during the first oscillating circle. This erosion phenomenon, attributed to a self-focusing mechanism, lacks a comprehensive explanation. Here we provided… More >

Zhesheng Zhao¹, Shuai Li¹, Rui Han^2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.012080

Abstract This study investigates the interactions between droplets and bubbles within water-in-oil (O/W) and oil-in-water (W/O) systems, a fundamental problem of bubble dynamics in binary immiscible fluid systems. Considering the density ratio between the two fluids and the bubble-to-droplet size ratio, we have refined the classical spherical bubble pulsation equation, Rayleigh collapse time, and the natural frequency. In our experimental study, we found that the Rayleigh-Taylor (RT) instability hardly develops on the surface of the droplet when the densities of the two liquids are comparable. This phenomenon is explained using the classic theory of spherical RT More >

Leilei Wang¹, Li Chen², Haihang Cui², Xu Zheng^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.2, pp. 1-2, 2024, DOI:10.32604/icces.2024.011434

Abstract The emerging technique of artificial micro/nano-motors [1] provides a vivid example of the idea using tiny machines to finish jobs in microscopic world. Among many micro/nano-motors, microbubble driven micromotor is a unique type that can reach the highest propulsion speed [2, 3], owing to the high surface energy of the bubble and the focused hydrodynamic jet during bubble collapse that can significantly enhance micromotor’s propulsion. Recent progress has demonstrated that the microbubble itself can implement new functions for the micromotor based on bubble dynamics and induced hydrodynamic flow, rather than merely providing energy. For instance,… More >

Tatyana Lyubimova^1,2,*, Yulia Garicheva², Andrey Ivantsov¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.11, pp. 2417-2429, 2024, DOI:10.32604/fdmp.2024.052391 - 28 October 2024

Abstract External vibrations are known to be one of the promising ways to control the behavior of multiphase systems. The computational modeling of the behavior of a gas bubble in a viscous liquid in a horizontal cylinder of square cross-section, which undergoes linearly polarized translational oscillations in weightless conditions, has been carried out. Under vibrations, the bubble moves towards the wall of the vessel with acceleration determined by the amplitudes and frequency of vibrations. Near the wall, at a distance of the order of the thickness of the viscous Stokes boundary layer, the effects of viscosity More >

Junhua Gong¹, Yujie Chen^2,*, Bo Yu², Bin Chen¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.4, pp. 1-2, 2024, DOI:10.32604/icces.2024.012531

Abstract Traditional interface reconstruction methods often rely on numerical approaches, which can be inefficient when dealing with large bubbles, requiring extensive computational resources. To address this issue, we propose a novel model based on convolutional neural networks aimed at rapidly and accurately predicting the equations governing circular bubbles. This model takes the volume fraction of the main-phase fluid surrounding each computational grid cell as input variables and is capable of precisely forecasting the coordinates and radii of bubbles. To further enhance model performance, we employ the Optuna hyperparameter optimizer to fine-tune the model's parameters. Upon training More >

Yang Cao^1,*, Jianshu Liu², Xuhui Meng¹

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 675-685, 2024, DOI:10.32604/fhmt.2024.051208 - 20 May 2024

Abstract Boiling heat transfer, as an efficient heat transfer approach, that can absorb a large amount of latent heat during the vaporization, is especially suitable for heat transfer occasions with high heat flux demands. Experimental studies show that the surface tension coefficient of pure water can be reduced sharply (up to 25%) when it is magnetized by a magnetic field applied externally. In this paper, magnetized water (MW) was used as the work fluid to conduct boiling heat transfer experiments, to explore the influence of magnetization on the boiling characteristics of pure water. The electromagnetic device… More >

Ayat N. Mahmood¹, Amer A. Abdulrahman¹, Laith S. Sabri^1,*, Abbas J. Sultan¹, Hasan Shakir Majdi², Muthanna H. Al-Dahhan³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 239-256, 2024, DOI:10.32604/fdmp.2023.028015 - 14 December 2023

Abstract Hydrodynamics characterization in terms of flow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies. This review presents recent studies on the typical flow regimes established in bubble columns. Some effort is also provided to introduce relevant definitions pertaining to this field, namely, that of “void fraction” and related (local, chordal, cross-sectional and volumetric) variants. Experimental studies involving different parameters that affect design and operating conditions are also discussed in detail. In the second part of the review, the attention is shifted to cases with More >

Meng Jia, Mingjun Pang^*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 337-366, 2023, DOI:10.32604/fhmt.2023.044286 - 30 November 2023

Abstract The interphase mass, heat transfer efficiency, and flow resistance are strongly dependent on bubble size in gasliquid two-phase systems, so it is very important for engineering applications to effectively control bubble size. In this paper, the formation, growth, and detachment of single bubbles in Newtonian liquids based on capillary needles were studied in detail using a volume of fluid method. The authors investigated the effects of gas injection velocity, gravitational level, surface tension coefficient, needle radius, and liquid−phase properties (liquid viscosity and density) on the process of bubble generation, and the effects of the above… More >