Modelling and measurement of unconfined bubbly two-phase plume flow

Abstract

<p>Bubbly plume flow, which is encountered in many refining processes of the iron and steel making industry, has been studied with a water model ladle and simulated with a novel mathematical model. The main achievements of this project can be summarized as following: (1) A new experimental technique based on the Laser Doppler Anemometry and Electrical Probe has been developed to measure various flow parameters of the plume, such as: mean and turbulent liquid velocities, bubble velocities and distributions of void fraction and bubble frequency. (2) The turbulence feature and bubble behaviour in the gas/liquid two-phase zone has been experimentally studied with the newly developed LDA/EP technique in a water model ladle. It has been found that turbulence in the plume zone is close to an isotropic one and the relative velocity of bubbles is not affected by the void fraction in the plume. (3) A mathematical model based on the modified k-ε turbulence model has been developed to simulate the plume flow. The coefficients of the extra source terms of the modified k-ε model have been determined experimentally. The mathematical model yielded good predictions of both the mean and the turbulent liquid velocities. The behaviour of bubbles in the plume has also been dealt with to produce good predictions of the void fraction distributions.</p>