Microbubble enhanced high intensity focused ultrasound (HIFU) is of great interest to tissue ablation for solid tumor treatments such as in liver and brain cancers, in which contrast agents/microbubbles are injected into the targeted region to promote heating and reduce prefocal tissue damage. A compressible Euler-Lagrange coupled model has been developed to accurately characterize the acoustic and thermal fields during this process. This employs a compressible Navier-Stokes solver for the ultrasound acoustic field and a discrete singularities model for bubble dynamics.
View Article and Find Full Text PDFMicrobubble enhanced high intensity focused ultrasound (HIFU) is of great interest to tissue ablation for tumor treatment such as in liver and brain cancers. To accurately characterize the acoustic and thermal fields during this process, a coupled Euler-Lagrange model is used. The ultrasound field is modeled using compressible Navier-Stokes equations on an Eulerian grid, while the microbubbles are tracked in a Lagrangian fashion.
View Article and Find Full Text PDFUltrason Sonochem
January 2018
The dynamics of a bubble cloud excited by a sinusoidal pressure field near a rigid wall is studied using a novel Eulerian/Lagrangian two-phase flow model. The effects of key parameters such as the amplitude and frequency of the excitation pressure, the cloud and bubble sizes, the void fraction, and the initial standoff distance on the bubbles' collective behavior and the resulting pressure loads on the nearby wall are investigated. The study shows that nonlinear bubble cloud dynamics becomes more pronounced and results in higher pressure loading at the wall as the excitation pressure amplitude increases.
View Article and Find Full Text PDFNumerical modeling of cavitating bubbly flows is challenging due to the wide range of characteristic lengths of the physics at play: from micrometers (e.g., bubble nuclei radius) to meters (e.
View Article and Find Full Text PDFThe effects of gravity on a phase separator are studied numerically using an Eulerian/Lagrangian two-phase flow approach. The separator utilizes high intensity swirl to separate bubbles from the liquid. The two-phase flow enters tangentially a cylindrical swirl chamber and rotate around the cylinder axis.
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