1988 Volume 14 Issue 5 Pages 593-600
In a draft tube spouted vessel fitted with a gas-liquid injection nozzle, average gas holdup and annulus liquid circulation velocity were measured over a wide range of operating conditions. Flow pattern variations were also observed.
In the range of lower liquid flow rate, the average gas holdup increased with increasing gas flow rate, but was not affected by liquid flow rate. In the range of higher liquid flow rate, on the other hand, the average gas holdup increased with increases in both gas and liquid flow rates. Relatively uniform fine bubbles were found to be generated by a liquid jet at liquid flow rates beyond the critical spouting velocity. Experimental equations were proposed to predict the average gas holdups. The annulus liquid circulation velocity tended to increase with increasing liquid flow rate, allowing bubbles to be entrained into the annulus of the vessel. It was also found that the liquid circulation velocity first decreased and then, after reaching a minimum value, increased. The effect of gas flow rate on the annulus liquid circulation velocity was significant at low liquid flow rates. The liquid circulation velocity was theoretically analyzed and correlated by using a simple flow model.
