Modeling the mass transfer at acoustically generated bubble interface using Rayleigh–Plesset equation second-order derivatives

Abstract

One of the many ways of cavitation utilized for process intensification is through acoustically inducing it. As acoustic cavitation gained traction in recent industrial works, numerical modeling became an important study tool to scrutinize and optimize acoustic cavitation applications. However, available hydrodynamic cavitation models are found incapable of accurately predicting acoustic cavitation structures and flow features. This could source from the oversimplification of the Rayleigh–Plesset equation or from obscure effects of empirical model constants. To address this issue, new mass transfer source terms for Zwart–Gerber–Belamri model were derived based on the consideration of Rayleigh–Plesset's second-order derivatives. In addition, a design of experiments statistical approach, coupled with Monte Carlo simulations, was implemented to assess the influence of empirical model constants on the model's performance by examining variations in amplitude and frequency responses. Moreover, a set of optimized model constants was obtained: evaporation constant = 17.359 88, condensation constant = 0.1, Bubble Radius = 25 × 10−6 m, and Nucleation Site Volume Fraction = 5 × 10−4, to obtain a maximum pressure and frequency of 3.62 bar and 4128.73 Hz, respectively. The new model, with the new constants, was configured into ANSYS Fluent 22.1 and validated against experimental values. The new model resulted with maximum pressure and frequency of 3.48 bar and 4894.56 Hz, respectively, validating the statistical model and showing drastic improvement in qualitatively and quantitatively capturing acoustic cavitation.

Behaviors of cavitation bubbles driven by high-intensity ultrasound

“…In the fifth acoustic cycle, pulsations were enhanced, and then equilibrium radii of the first two bubbles expanded, which might be due to the mass transfer through bubble surfaces. [27,28] Several violent collapsing spikes were observed (marked by empty circles), which might be related to abrupt perturbations of the surrounding acoustic pressure and strong interactions among bubbles. According to the radial oscillations, we predicted the secondary radiation pressures of bubbles as shown in Figs.…”

Numerical Study of Geometric Characteristics and Coalescence and Breakup Behavior during the Rise of Multiple Parallel Bubbles

“…There is an increasing need for efficient resource utilization and process intensification in various industries. One key aspect of achieving this efficiency lies in understanding gas–liquid multiphase flow and its applications in industries such as power, coal, metallurgy, petroleum, chemical, etc. , Within various chemical engineering equipment, such as reactors and bubble columns, the flow of bubbles is a common phenomenon. Grasping the dynamics and behavior of bubbles in multiphase fluids is crucial for process control and optimization. , Bubbles frequently experience coalescence and breakup.…”