Abstract
The gas holdup and average rising velocity of bubble swarms in a mercury bath have been studied by using an electroresistivity probe method. The column diameter was 7 cm and the bath depth was 40-70 cm. Nitrogen was blown through a nozzle (O.D. ×I.D. =0.7×0.2, 0.4×0.24cm) into the bath. The gas-flow rate was 160-1330 (cc/sec, 1 atm). It is found that the gas holdup is 0.073-0.28 and the average bubble rising velocity is 50-100 (cm/sec). The gas holdup of the present nitrogen-mercury system is nearly equal to that of the air-water system. Equations are obtained to describe the effects of physical properties of gas and liquid on the gas holdup. The equations are used to explain the close agreement of the gas holdup between the two systems. The effects of column and nozzle diameters on the gas holdup are also examined. From theoretical analyses of the data, the gas holdup and average bubble rising velocity are estimated for the nitrogen-molten iron system.
