Swirl Motion in a Cylindrical Bath Agitated by Top Lance Gas Injection

Abstract

Researches on top lance gas injection in a cylindrical bath are carried out based on water model experiments. The penetration depth of bubbles and a swirl motion are investigated because of their practical importance. Empirical equations are proposed for the penetration depth as a function of a modified Froude number. A bath surface oscillation map is drawn in order to identify the occurrence condition of the swirl motion, and then empirical equations are proposed for describing the occurrence condition of the swirl motion. The characteristics of the swirl motion are also analyzed, and empirical equations are proposed to predict starting time, period, amplitude, and damping time of the swirl motion.

Hydrodynamic Simulation of Gas - Particle Injection Into Molten Lead

“…Figure 10 shows the residence and mixing determination times for different lance (Figure 10a) and kettle (Figure 10b) sizes for a flow rate of 3.3155 m s -1 . the gas flow rate is increased, a continuous jet is promoted, inclusively, a swirl motion on the liquid surface is reached 31 . It was observed the formation of a gas channel during the gas injection instead of the formation of discrete bubbles under all of the simulated conditions.…”

“…If the super-saturation pressure with respect to the transferred component exceeds P g , the bubble will grow until it reaches a size where the buoyancy forces exceed the surface tension forces and detachment occurs. It has been reported a transitional range based on Reynolds number 30 and modified Froude number 31 , where the bubbles form a continuous jet or discrete bubbles according with the gas flow rate. Generally, the inertial force of gas injected in from the top lance in the low gas flow rate is not strong, therefore there is a forming of discrete bubbles and when enough to assume that the initial velocity of the bubble will be close to final, leaving the particle on the liquid surface.…”