Abstract:
Submerged gas injection has attracted much attention due to its wide range of
application in different processes. A number of numerical analysis has been made to
investigate the stability of submerged air jet in liquids. Experimental studies are
however scarce. In present study for the first time a systematic experimental study of
submerged gas jet is made. Experimental investigation on submerged air jet was
carried out in a 14x 14 cm2 Perspex column with a liquid height of 25 em. The jets
were generated by flowing air at different velocities through nozzles immersed at the
bottom of a stagnant liquid column. The diameters of the nozzles used were I, 4 and 6
mm. The jet formation was observed in three different liquids, namely, water, ethanol
and glycerol. The minimum jet formation velocity was recorded and jet lengths at
different velocities were measured by image processing. The data showed that the jet
length increases as the velocity increases until it reaches a maximum value. Beyond
this value, the jet length decreases as the velocity increases. The jet formation
velocities as well as the jet lengths for all three gas/liquid systems are increased with
decreasing nozzle diameter. Viscosity of the liquid was found to have a destabilizing
effect on jet break-up length. The observed phenomena are explained with the aid of
instability theory and compared with existing theoretical analysis.
