Effect of Input Power and Temperature on the Cavitation Intensity During the Ultrasonic Treatment of Molten Aluminium

Abstract

Experimental results of ultrasonic processing of liquid aluminium with a 5 kW magnetostrictive transducer and a 20 mm titanium sonotrode excited at 17 kHz are reported in this study. A unique high-temperature cavitometer sensor, placed at different locations in the liquid melt, measured cavitation activity at various acoustic power levels and different temperature ranges. The highest cavitation intensity in the liquid bulk is achieved below the surface of the sonotrode, at the lowest temperature and when the applied power was 3.5 kW. This two-fold mechanism is related to a) acoustic shielding and b) the tendency of liquid aluminium to release hydrogen when the temperature drops, thus promoting multiple cavitation events. Understanding these mechanisms in liquid metals will result in a major breakthrough for the optimization of ultrasound applications to liquid metal processing.

Dynamics of two interacting hydrogen bubbles in liquid aluminum under the influence of a strong acoustic field

“…The resonant frequency f i0 of a bubble i with an equilibrium radius R io is given by the Minnaert relationship [28] , and κ is calculated using equation (6) since G 1 G 2 ≪ 1 for the range of frequencies and radii considered in this study. These conditions are commonly met by experimental setups for which measured acoustic pressures and frequency spectra are available [29].…”

Intensification of Sono-Assisted CO2 Stripping/Carbon-Rich Solvent Regeneration by Fe2O3 Hydrophobic Micronized Particles

“…The reason for conducting an experiment at low temperature is that increasing the reaction temperature allows cavitation to be achieved at a lower acoustic intensity. To obtain the maximum sonication benefit, experiments should preferably be conducted at low temperatures or with low vapor pressure solvents. − After regeneration, the carbon-lean samples were collected and subjected to the carbon loading test, and the measured values are tabulated in Table . The measured lean carbon loadings after solvent regeneration were 0.364, 0.352, and 0.323 mol CO 2 /mol of solution when exposed to sonic frequencies of 360 kHz, 470 kHz, and 1 MHz, respectively.…”

Influence of Piezoelectric Properties on the Ultrasonic Dispersion of TiO2 Nanoparticles in Aqueous Suspension

“…The value measured at the center of the ring-shaped piezoelectric ceramic for the hard PZT was about 20-110 mV, while the value measured for the soft PZT was less than 35 mV, showing relatively weak voltage compared to the hard PZT. This indicates that an increase in the input voltage (VRMS) does not result in a corresponding increase in the cavitation activity [33].…”