Numerical Simulation of Molten Steel Flow Field in a Ladle Induced by Low-Frequency High-Power Ultrasound

Abstract

To encourage the use of ultrasound in the calcium treatment of molten steel, this study utilizes the volume-of-fluid (VOF) method combined with a mixture model to analyze the distribution of the flow field in molten steel when ultrasound is applied. The effects of low-frequency, high-power ultrasound on the pressure field, volume fraction of cavitation bubbles, velocity distribution, and turbulence intensity are investigated. The results reveal a pattern of alternating positive and negative pressure in the pressure field during each cycle, with the lowest pressure measuring −9.63 × 104 Pa at 96 kW. The cavitation bubbles are concentrated in the intense cavitation area beneath the ultrasonic probe, exhibiting a maximum volume fraction of 2.50 × 10⁻². The axial velocity peaks at the central axis, whereas the radial velocity is negligible. The maximum axial velocity increases from 0.36 m/s at 48 kW to 0.82 m/s at 120 kW. This velocity trend mirrors the turbulence intensity distribution, with the highest turbulence intensity of 276 at 96 kW. These findings provide a theoretical basis for low-frequency, high-power ultrasound to improve the calcium treatment of molten steel. The outcomes of the numerical simulation closely align with the experimental results, substantiating their reliability through a comparison with published studies.